hi,i have succesfully overlaid many sets of wooden car dash parts but the only plastic set i tried failed in the heat of the car,ie the carbon lifted off the part…BUT i did another plastic part,much larger as in pic and this has never lifted at all…
question is i did this 3 years ago and i cant remember what i did differently to the 2nd part which means its still ok today??? did i use epoxy resin on for the tacky layer or something else? i genuinely cant remember!
thanks
Here’s my shotgun guess post.
Did you scuff up the other part? Did clean it thoroughly before laying up on it?
Did you use the same resin?
Are you sure it was made of the same plastic?
Is one part exposed to direct sunlight more often than the other causing lifting there? Or maybe shocks?’
Are any of the above questions helping you figure out what you did?
i THINK the issue was that the part was painted by the manufacturer and i didnt realise this so the resin only bonded with a scuffed up layer of paint…am trying another bit now that by the time i sanded all the paint off ended up as white ABS.
A piece of trivia I learned in class was along these lines. Manufacturer’s for mass production cars, which in the car world is really ~$100,000 and less, just make a generic color part and spray it or silkscreen whatever color for production purposes. This is what one of those 2 second general facts one of my professors threw out during class, so yea it may not be true for all cars but I’m confident most budget cars are produced like this,
should polyester(surfboard) resin stick ok to the ABS??
thanks
I’ve never tried bonding polyester resin to ABS but if you scuff up the part enough it should be fine. I built a greenhouse out of plexiglass and the polyester resin sticks the surfaces well. I just went outside and tried to scratch some off with my fingernail and it didn’t come off Surfboard resin might gives you problems though because it may contain wax.
If you’ve got doubts grab a test piece from a junked car and test it on that. Also Legos are made from ABS and the black pipe from Home Depot is likely ABS as well. If you want I can go test it myself and report back with results.
Silmar 249 from US Composites does not contain wax, and is a great poly resin. As far as its ability to stick to ABS, I don’t know. It does seem to handle heat pretty well though, so it should do well for doing car interior parts.
i am indeed doing a test piece at present but only have surfboard resin here…but i do have some west epoxy that i could maybe use for the stick on layer of resin? its maybe 3 years old now though so not sure how good it would be plus being epoxy it takes forever to dry i seem to remember?
i dont think completing the test piece will be an issue but im more concerned about its long term survival in a hot car,im thinking i can test this piece in my oven for several hours at 120f???
If you want to be even more thorough with your test, cycle the piece, so bake it at 120 then put it in a refrigerator, then bake it again, and just continue until your satisfied that it’s not debonding.
good point,thats exactly what i will do :)will report back when complete…thanks
i finished the test piece,obviously needs a final buff here but not too bad…one problem is that when i sanded all the paint off the abs was white,i used a black dye in my base resin coat but looks like i should have used two as you can see white patches coming thru the weave in a couple of spots…but overall its ok for a test bit.
how long should i let it cure before i try the heat cycling tests??
It looks like a very nice looking piece. What do you use to cut the edges? It’s very clean.
As for testing check out the specifications on you resin. It should list a gel time, a handling time, and a full cure time. For one resin system I have the gel time is 4 hours, the handling time is 36 hours and a full cure is 7 days. Another one is 30 minutes gel, 16 hours handling, 48 hours full cure. Test your part after it’s fully cured.
i used a dremel,VERY carefully! followed by a sanding block…
i tried it in my car,its not the proper one for my car hence it being a scrap test bit before i do the proper one…
here is the white showing thru the weave,how should i prevent this next time?? i used black dye in the resin but it didnt coat very well,maybe 2 coats or even a layer of fibreglass tissue??
More black resin. Before you lay up paint the part black until you can’t see white anymore and then layup on it. Or you could try another layer of CF which will reduce the chance of white showing up on the background
got 7 bits to start tommorrow so will double up on the resin and see how black they look,dont really want to double up on the carbon as its expensive and will make the part too thick…the bit i used in this piece was an old scrap and not off a roll so the weave was a little distorted to begin with…
Maybe you could try finding a black paint that will stick well to both the plastic and epoxy?.. maybe a thin layer of black gel coat? Just an idea.
I have had luck coloring ABS and other plastics with Rit Dye. It can be found at almost any grocery store and is very inexpensive. http://www.ritdye.com/home.lasso
most who do overlays tint the “glue down” resin with black dye. I scuff parts with 40 or 60 grit paper prior. Wash it a couple times with dishsoap and water. rinse thouroughly. tinti resin black, brush it on. let it get super tacky… past the point of super tacky so the black resin does not absorb thru the carbon fiber ( thereby ruining the cf cloths look ). Let that sit for 24 hours after you apply the cf. Then apply your clear coating layers. Final sand the part, wash it with soap and water. Wash it with solvent based paint supply cleaner ( sherwin Williams has it) and 2 part urethane clear coat the part. Other clear coats simply will not hold up to sunlight and time.
West Systems epoxy resin is awesome for gluing cf onto a plastic scuffed part. Some epoxies work like sh*t on plastic and just won’t adhere for long. On the other hand West Systems resin 208 or 207 special clear is a real pita to get all the tiny air bubbles out of when using for top coating. It is pretty thick stuff. I use a local supplier for the clear coat epoxy that has about a 600cps viscocity.
Kleer Koat brand ( US composites ) epoxy sucks for yellowing… it yellows very badly in sun. Many clear epoxies do suck for UV hold out. I just got lucky with the brand we use as it yellows slowly over time.
If you want to test your resin do a destructive test of an overlaid part. We do this from time to time for quality control purposes.
thats EXACTLY what i already do…