I have built many plastic kits using either Testor's liquid plastic cement or Ambrose Safe Weld with excellent results. In the last couple of days I have started my forst two DPM kits. Neither of the cements I usually use seem to be very effective, melting the plastic very little. resulting in very weak joints.
What do you DPM modelers out there recommend?
Roger,
You need a more aggressive cement, also DPM recommends, washing the parts in soapy water, to remove any residue, left from the molds. Testers is not strong enough and the new formula, Ambroid, won't work either. Tenax, Plastruct Bondene, Plastruct Plastic Weld and if you can find it, original Ambroid Pro Weld, will work. If you are not afraid of, hazards, or smell, real Lacquer thinner, will work. Try on the backside of a part, put a dab,of glue on it, within 5-10 seconds,if it does not become tacky,or sticky, it will not work.
Cheers,
Frank
I've generally had good results assembling flat walls with Testors' liquid. As long as there's enough flat surface, like the pilasters-to-wall joints, it works fine. How old is your glue? When mine gets down to the bottom of the jar, I find it's not as effective as a fresh bottle, particularly if it's gotten contaminated with a bit of paint from earlier jobs.
Anywhere else, I add extra pieces of scrap styrene inside the building. For corners, I use 1/8 or 3/16 square balsa wood strips, and put them together with CA.
Where I'm painting a section before assembly, I make sure to mask the plastic mating surfaces with blue painters' tape to keep them clean.
It takes an iron man to play with a toy iron horse.
Does plastic lose its plasticity over time? The DPM kit I am working on was purchased several years ago (maybe as much as ten years ago). the plastic seems to be quite hard and brittle.
Since neither Testors or Ambroid liquid cements have not softened the plastic enough do a good bond this afternoon I purchased some Tenex 7R. Out seems to be more effective but only slightly. I cemented a couple of scraps together but after an hour I was easily able to separate them. The cemented surfaces showed little signs of a bond.
I've always used Testor's model cement (red tube) on DPM kits with good results.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
I use lacquer thinner for my DPM modular stuff:
...and for Walthers kits and scratchbuilt plastic structures:
...and pretty-much anything in styrene:
Wayne
Testors Model Master Liquid Cement for Plastic in the needle nosed black plastic bottle is what I use for the DPM structures and it works every time'.
http://www.testors.com/product/136942/8872C/_/Liquid_Cement_For_Plastic
Rich
Alton Junction
jeffrey-wimberly I've always used Testor's model cement (red tube) on DPM kits with good results.
Jeff,I use that as well with excellent results.
I tried Tenax 7R on DPM kits never again and I will never buy that brand again since IMHO its a complete waste of money.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
skagitrailbirdNeither of the cements I usually use seem to be very effective, melting the plastic very little. resulting in very weak joints.
Just out of curiosity, are you putting the cement on the faces (edges) of the parts to be joined, or are you butting the joints together and then putting the cement on the seam from the back side?
maxman skagitrailbird Neither of the cements I usually use seem to be very effective, melting the plastic very little. resulting in very weak joints. Just out of curiosity, are you putting the cement on the faces (edges) of the parts to be joined, or are you butting the joints together and then putting the cement on the seam from the back side?
skagitrailbird Neither of the cements I usually use seem to be very effective, melting the plastic very little. resulting in very weak joints.
My thoughts as well. It may be more a issue of application technique rather than the cement itself.
I have found that quite thin/ quick drying liquids will evaporate before proper bonding if not applied liberally to the joint. For rather large surface area joints, I will use may Fav, Faller Xpert or Testor's Model Master. These cements are a bit thicker and don't evaporate that quickly allowing some added time for positioning the parts. For laminating or bonding long/ large seams, brushing/ wicking the thinner solvents (from the backside) should produce a solid bond as well.
Modeling B&O- Chessie Bob K. www.ssmrc.org
The vertical edges of the DPM modular wall panels are rabbeted, leaving a slightly thinner strip about 1/8" wide down each side. Two panels are then butted together and a pilaster is cemented into that recessed vertical trough keeping all three parts perfectly alligned and straight. I haven't tried it but I am concerned that working grom the back will make it difficult to be sure the pilaster is properly seated in the groove and that everything is properly alligned. I'll try to rig up some sort of jig and give it a try.
Try using small clamps. I picked up a pair of them (2 for $1.50) at a show a while back, and liked them so much I bought more. They are perfect for holding together small sections, and I think the immediate pressure applied for just a few minutes gives me a very strong bond. I've been putting together a Walthers Cornerstone modular kit, and I use the clamps for just about every joint. It speeds the whole job up, because I don't have to stop and hold things together manually.
Good idea. And I already have a couple of dozen clamps. I'll give it a try today. Thanks!
I use orange tube Testors glue. Works fine. My technique is to use drops of glue rather than a steady bead, which is overkill, IMO. Specifically, I alternate drops of super glue and Testors. The CA provides a quick bond to hold the pieces in place while the Testors cement dries to provide the long term stable bond.
For long walls built from DPM modulars, I use long pieces of strip styrene cemented to the back of the wall to provide straightness to the wall as well as additional strength. They also provide a base for the roofs, which I typically make from cereal box cardboard. When strenghted by homemade L girders made from the same material, and spray painted with rattle can texture paint, the cardboard roofs are quite sturdy as well.
Additionally, all of these walls get foundations made from long strips of styrene. The foundations provide additional strength.
- Douglas
DoughlessAdditionally, all of these walls get foundations made from long strips of styrene. The foundations provide additional strength.
That's another good practice. I like to put at least some rudimentary interiors in all my buildings. I use 1/4-inch foamboard, because it's cheap and easy to work with. I discovered early on that adding a second floor inside the building made for a very solid model, as the foamboard added a lot of dimensional stability for negligible cost and weight. I support these interior floors with 1/8 or 3/16 balsa strips glued to the inside walls with CA.
skagitrailbirdThe vertical edges of the DPM modular wall panels are rabbeted, leaving a slightly thinner strip about 1/8" wide down each side. Two panels are then butted together and a pilaster is cemented into that recessed vertical trough keeping all three parts perfectly alligned and straight. I haven't tried it but I am concerned that working from the back will make it difficult to be sure the pilaster is properly seated in the groove and that everything is properly alligned.
For gluing relatively large surfaces such as the backs of the pilasters to the DPM wall sections, use a larger brush than that which comes with the commercial solvent cements. A 1/2" brush holds more solvent and can cover those surfaces in one pass, often without re-filling the brush. I generally assemble those walls against a straightedge, and there's no need to work from the back side of the wall.
Here are the insides of the National Grocers buildings shown earlier:
For larger projects, such as styrene street surfaces, I use a 2" brush - if you accidentally apply too much solvent, let it sit for a few seconds to allow the excess to evapourate.
Also note what wasn't mentioned - the little rectangles of styrene forming gussets over the joints along the curved wall, as well as the obvious diagonal brace. And the strip styrene along the right hand (in the photo, as shown upside-down) wall and the little projection to thr rear. That's what makes for a sturdy structure that won't fall down the first time you try to position it, or do something extreme, like flip it over to show how it's made.
I'm becoming convinced to try straight laquer thinner instead of the fancy solvents - it seems aggressive enough to melt the plastic to make a good weld, yet not so aggressive that accidently touching some place you didn't mean to glue will leave a huge mark if you just let it alone to evaporate without touching the spot.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Yesterday I experimented, incorporating suggestions from several respondents.
i cemented four wall panels upside down against a straight edge. Using a medium sized brush i flooded the backside seams with Testor's liquid cement. I put some weight on each seam overnight. This morning the bond felt quite solid but I think some bracing will be in order
I've had no luck with Tenax either. I've been told to keep it in the fridge to slow down the evaporation time, but I just couldn't get anythiing to stick using it. I haven't tried gluing a DPM kit yet though. But I figured if I couldn't get styrene to stick with the Tenax then I wasn't going to try it with more "difficult" plastics. I know it's a favorite cement/welder for many but it just doesn't seem to like me. Glad to read of other suggestions when my own favorite (Ambroid Safe-Weld) wo't cut it.
Jim
Raised on the Erie Lackawanna Mainline- Supt. of the Black River Transfer & Terminal R.R.
I just spent the past few days putting my first DPM modular together. This is following having just finished my first Cornerstone modular structure. I used the testor liquid cement ( the one with the brush) on both. It's my epxperience that the DPM plastic reacts differently, and not as well to the liquid glue, as the Cornerstone parts do. And the good old red tube of Testors seemed to work better on the DPM parts than the liquid cement did.