Cutting the foam

[KingConrail76]

Oh please. You obviously have never tried. I have cut pink foam with my radial arm saw to create bridge abutments with superb results.

gh

That's a bit harsh.

If you were to read the thread from beginning to end BEFORE quoting and replying to a post from a week ago, you would have noticed that BOGP40 has reposted about his comment, explained his method, and then retested with different results.

Would it be fair of me to say...You OBVIOUSLY just wanted to attack someone elses comments...?...No it would not!

[olequa]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

Oh please. You obviously have never tried. I have cut pink foam with my radial arm saw to create bridge abutments with superb results.

gh

 

[chatanuga]

For my layout, I scored where the cuts were to be with a utility knife and then completed the cut with an old serrated steak knife.  While the edges aren't 100% smooth, I plan on covering them later with a fascia.

Kevin

http://chatanuga.org/WLMR.html

[nof]

I have been cutting the 2" foam for my layout with a (partly) home made hot wire table saw. I have even cut circlesegments with it. you can see it on my web page.

I have also used a router and the high revs will make very nice edges.

[ICRR1964]

bogp40 had some really good points on "cutting the foam" I never did try it with the worm drive saw, because of the weight of the saw, but after reading his post it sound hard to do. I use my jobsite 10" table saw when we are doing siding or rafter insulation and this works well, as stated dust is a problem. When doing fan fold under siding I use a knife because it is easier. Fighting the wind while trying to put the fanfold up is know fun though. LOL!

[Zandoz]

My few cents worth......

For straight-n-square cuts I've gotten the best results with a 7-1/4" table saw and an 80 tooth plywood blade

2nd best for straight-n-square came from a hybrid method....an old battery powered B&D 3-3/8" circular saw...following up with a utility kinfe finishing the cut on thicker sheets, using the kerf cut by the circular saw as a guide.

I've tried various types of jig saws...not bad for 1" and under, but on thicker the blades tend to wag leaving a nice neat cut on the top surface, but a scalloped effect by the time the blade gets through the bottom surface.

Score and snap has worked OK on thinner foam...poorly more often than not on thicker.

For curved cuts, I've not found anything that works well...but I will be experimenting with using a Roto-Zip tool when the weather gets better and I can cut outside.

On the HD & Lowes panel saws...I've tried to get several to cut foam on them, and all have refused.  Two said that it had been tried before and the foam "exploded" when the saw hit it...the others just said it's against policy.

[jktrains]

The more teeth the better along with high rpms.  When I first suggested cutting foam on a table saw my friend was just a skeptical.  After the first cut he was convinced.  It allows you to get accurate, square cuts that you can't get with a score and snap method nor the extended utility knife since the blade will flex.

[concretelackey]

I'm not in commercial at all. I work for a precast company that makes precast concrete residential basements in a plant, we deliver and install on the home owners site. All the basement insulation and studding is part of the wall system.

Actually, now that I think of it, we have done a few commercial jobs. Maybe 2 or 3 dozen though.

Back to the thread. As bogp40 stated, high speed blades are the key and using the table saw is the best.

[bogp40]

Bogp40, Have you ever tried cutting foam with a power tool?  Based on you response I would say, no you haven't.  So before replying, make sure you speak from some level of experience.

Actually yes, tried cutting various thickness on site many times and the results were poor. However, I have been using a worm drive for over 25 years on the job.

Today, I experimented with cutting 1" and 1 1/2" Owens Corning. With everyone saying that power tools do such a great job, I wanted to find out why I wasn't getting a decent edge.

The worm drive, awkward and heavy to run through a light product is part of the trouble, It did as I have always found. Put a 24 tooth carbide (new) and the cut was better but still unacceptable.

Used a Makita 7 1/4", even with a so-so blade, to my surprise the cut was not bad. Didn't have a new blade to find if the cut would be better (diamond already knocked out of the new 24t) Only had new framing blades on site.

I then ran both sizes through the table saw (newer 10" 60 tooth Freud). It made the best cut and was almost as good as the factory edge.

Tried a Bosch jigsaw. Destroyed the edge with a med/ coarse blade, much better with a fine and even better with the reverse pitch tooth (those twin tooth reversed Bosch blades)

I came to the conculsion that a higher RPM skillsaw or table  saw, and the greater no. of teeth the finer the cut. The worm is a much slower saw and produces the worst cut of all, plus is a very awkward tool to use for this purpose.

I cut and install the extruded foam on a regular basis, nothing like concretelakey on those large commercial installs though. Most of the foam I use is for sidewall fan fold 3/8" or sheet 3/4" under vinyl siding. My other common uses are for insulating odd framing of boxed bays, head and seat boards (both sandwiched interior or exterior) for angle bays and bow Andersen windows.

Now that I know some of these other pieces of equipment will do the job, cutting foam this way may be an option. However, most times the utility knife still seems the safest method for most of my applications. These tools may not be set up, working on ladders or staging, or just the overall safety of setting up, weighting the light product on stable and well supported horses and cutting with a skillsaw just wouldn't be productive or even safe in most instances.

If I was to rip numerous panels for insulating basement sleepers or rafter bays, as concretelakey seems to do regularly, the table saw would be the way to go.

So all these years of cutting, or not wanting to cut the foam you lean something new.

So now Ithink it's time to go to the "Diner" for some of that humble pie.....

[Mailman56701]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

WRONG!  I've cut many a sheet with either a table saw, radial arm saw, circular saw and even a router.  All leave a smooth, square cut better than what you will get with scoring and snapping.  I have had HD refuse to cut it on their panel saw before though while Lowe's said sure no problem. 

Bogp40, Have you ever tried cutting foam with a power tool?  Based on you response I would say, no you haven't.  So before replying, make sure you speak from some level of experience.

I agree from experience that a circular type power saw will give a better than factory edge but at the same time I'll say that a reciprocating blade (saw-zall/jig saw) will chew the foam like a dog chews on shoes. Perhaps those that are concerned about cutting it with a power tool have experience only with the reciprocating blade tools?

  Well, after getting it cut via a panel saw so that it'll fit into my car, I use a jig saw at home to cut into desired widths, etc., and it too cuts just fine.

[concretelackey]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

WRONG!  I've cut many a sheet with either a table saw, radial arm saw, circular saw and even a router.  All leave a smooth, square cut better than what you will get with scoring and snapping.  I have had HD refuse to cut it on their panel saw before though while Lowe's said sure no problem. 

Bogp40, Have you ever tried cutting foam with a power tool?  Based on you response I would say, no you haven't.  So before replying, make sure you speak from some level of experience.

I agree from experience that a circular type power saw will give a better than factory edge but at the same time I'll say that a reciprocating blade (saw-zall/jig saw) will chew the foam like a dog chews on shoes. Perhaps those that are concerned about cutting it with a power tool have experience only with the reciprocating blade tools?

[jktrains]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

WRONG!  I've cut many a sheet with either a table saw, radial arm saw, circular saw and even a router.  All leave a smooth, square cut better than what you will get with scoring and snapping.  I have had HD refuse to cut it on their panel saw before though while Lowe's said sure no problem. 

Bogp40, Have you ever tried cutting foam with a power tool?  Based on you response I would say, no you haven't.  So before replying, make sure you speak from some level of experience.

[concretelackey]

if you tie it to the roof of your car, make sure you have it secured from ALL FOUR directions.  Otherwise it will fly off the roof of your car while you going down the road and it'll break into 3 weirdly shaped pieces (but they'll still fit together!)  haha

 

Very good point here!!!! If it must be secured to a car roof I suggest 2 courses of action.

1-if hauling it as a 4x8 purchase 6 pcs of dirt cheap 1x2 lumber, place 3 on the roof spaced at 22" centers, lay the foam done on it, and lay the other 3 on top. If hauling as 2x8 you need 4 pcs of 1x2, 2 at each edge top and bottom. Secure it well and drive carefully....

2- If you have 2 sheets of thin plywood approx. the size that you are bringing home just sandwich the foam in between.

[concretelackey]

If you are making a 4x8 into 2 pcs 2x8 all you need is a tape measure AND IF IT IS 1" DOW BLUE BOARD.... pull out about 26" or so of tape, pinch the tape at the 24" mark, place your pinched fingers up against the edge of the foam, apply some pressure on the clip end of the tape and slowly (AND I MEAN SLOWLY) pull it evenly end to end. Now move to the end of the sheet holding each side about 8" from the corner and push down across your knee slowly.

The reason for pulling the tape slowly is two-fold....one is to make a consistant line without any squiggles (bet you have not heard that in a while) and second is the foam, your fingers and friction generate enough heat to cause some painful brush burns.

Cutting the board with a power saw (not a reciprocating saw) while give a better edge than the factory, and yes, it makes a heck of a lot of dust.

Now for the nay-sayers of what I have suggested here....Where I work we use about 800 to 1000 sheets of 4x8 1" DOW PER WEEK. Of that number about 250-500 sheets are scored and snapped as I described. After 20 plus years of my employer doing this method, yes on occasion some have snapped off the score line, but the vast majority are dead on line.

As for thicker DOW, we use 800 to 2000 pcs per week of 2 1/2" and 150 to 500 need to be scored, cut and snapped. Score your line and use either a thin putty knife (2 or 3 passes with get thru easily) or a NON SERRATED kitchen knife.

[DeadheadGreg]

if you tie it to the roof of your car, make sure you have it secured from ALL FOUR directions.  Otherwise it will fly off the roof of your car while you going down the road and it'll break into 3 weirdly shaped pieces (but they'll still fit together!)  haha

 

[Mailman56701]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

WELL, EXCUSE ME FOR MAKING A SUGGESTION!!!

As I have a truck now, I have never asked to have foam cut for me, but I regularly cut it on my table saw and find it makes for a very clean crisp cut. It DOES NOT rip and tear and make an "awful cut" as you PROCLAIM!!! Not to mention, HD HAS a dust collecting system, and they would have no complaint about the fuzzy dust. How do you suppose DOW cuts the stuff into 4x8 sheets?? look at the edges and you'll see the saw marks.

  Yeah, I get it cut by lumber yard workers on a panel saw all the time.  Works just fine.

[ICRR1964]

I Have been in the building industry for years now and we cut it 2 ways, when I have put in 2" between ceiling rafters in a garage, we rip them on a table saw or a 7.25" Skil Saw. We also use the knife that tsage has pictured, the saw method make a mess though. When cutting with a power say, use a carbide tip blade and finer tooth.

[KingConrail76]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

WELL, EXCUSE ME FOR MAKING A SUGGESTION!!!

As I have a truck now, I have never asked to have foam cut for me, but I regularly cut it on my table saw and find it makes for a very clean crisp cut. It DOES NOT rip and tear and make an "awful cut" as you PROCLAIM!!! Not to mention, HD HAS a dust collecting system, and they would have no complaint about the fuzzy dust. How do you suppose DOW cuts the stuff into 4x8 sheets?? look at the edges and you'll see the saw marks.

[vsmith]

[mammay76]

Just simply ask the HD or whatever store's employee for some help, and they will gladly cut it for you. tell them the measurements you need, and they will score it and snap it. they have always done it for me with no problems. i too suffer the no pick-up blues.....so instead of being THAT GUY driving down the road with wood hanging out my dodge neon's window, i would go to HD with my benchwork drawings with a cut list and get all my cuts done there...the one time they cut it wrong, they gladly told me to get another piece at no cost to me!  Good Luck! 

[bogp40]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

No! You need to cut it as described. I don't think even the HD workers will put foam in the panel saw. A saw blade will tear it and make an awful cut.

[KingConrail76]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary

My local Home Depot offers the first rip of ply wood for free and something like $0.50 for each additional....Maybe they'll rip it on the panal saw for ya at no charge.

[Don Z]

Yes, you can score and snap the foam sheets. It will snap cleaner if it is cut with the length of the sheet compared to across the sheet.

I usually score it a couple of times with my razor knife, then snap it to finish the cut.

Don Z.

[loathar]

I use those cheap retractable razor knives and a straight edge. The ones with around a 6" retractable blade that has the break off tips.

[Anonymous]

Ok, here's my dilema. I have to get a 4 x 8 piece of blue foam into my car. I need a 2' x 9' piece for my layout. If I cut the dimensions I need at the local builder's store it'll fit into the car and I won't have to borrow a pickup. So my question is how can I cut the foam at the supply store? Can I just score and snap it like drywall somehow?

 Thanks for any replies.

 

Gary