Pepakura help


I tried doing pepakura for the first time a few weeks ago. I had a problem when adding resin to my finished model. The resin directions said to put it in a warm environment to cast properly but it did not cast after I put my cast in a warm place after adding a few layers of resin. Any tips on how to put resin properly?
 

TurboCharizard

Division PR, RXO and BCO
Division Staff
405th Regiment Officer
Member DIN
S068
I tried doing pepakura for the first time a few weeks ago. I had a problem when adding resin to my finished model. The resin directions said to put it in a warm environment to cast properly but it did not cast after I put my cast in a warm place after adding a few layers of resin. Any tips on how to put resin properly?
Out of curiosity, what kind of resin are you using? Most of the ones that I've used list working temperature ranges but haven't included instructions to put the piece in a warm place for full cure.
 

PlanetAlexander

Well-Known Member
Some possible causes for that might be
1. There was foreign material that got into the mixture which prevented it from curing - something like even a slight bit of oil or another chemical (make sure all the tools are clean)
2. There might have been incorrect measurements, make sure to properly measure it (not just by eye) and that you check whether you need to measure volume or weight
3. Make sure you mix it well - very well. Scrape the sides and bottom of the mixing tub, as if it's not mixed thoroughly, it can improperly cure
 
Last edited:

TurboCharizard

Division PR, RXO and BCO
Division Staff
405th Regiment Officer
Member DIN
S068
I was using epoxy resin for casting and coating as the package said. It was still sticky after a day
I think the big issue here is choice of resin. Generally folks use fiberglass resin (a polyester resin) for the hardening stage and not an epoxy casting resin. What's the cure time on your epoxy?
 
Some possible causes for that might be
1. There was foreign material that got into the mixture which prevented it from curing - something like even a slight bit of oil or another chemical (make sure all the tools are clean)
2. There might have been incorrect measurements, make sure to properly measure it (not just by eye) and that you check weather you need to measure volume or weight
3. Make sure you mix it well - very well. Scrape the sides and bottom of the mixing tub, as if it's not mixed thoroughly, it can improperly cure
H
Some possible causes for that might be
1. There was foreign material that got into the mixture which prevented it from curing - something like even a slight bit of oil or another chemical (make sure all the tools are clean)
2. There might have been incorrect measurements, make sure to properly measure it (not just by eye) and that you check weather you need to measure volume or weight
3. Make sure you mix it well - very well. Scrape the sides and bottom of the mixing tub, as if it's not mixed thoroughly, it can improperly cure
How do I mix and measure resin?
 

Cadet

Executive Officer
Division Staff
Community Staff
Member DIN
S111
How do I mix and measure resin?

For that, we'll need to know exactly what type of brand you are using, style and the Brand Name. Most Epoxy Casting resins will give you the mixing directions and ratios on the container themselves, or with the instruction sheet. For example, I have used an epoxy casting Resin from Smooth On in the past on the interior of a Pepakura piece, to almost sort of use the paper model as a disposable mold and Slush Cast it. In that case, the Epoxy casting resin was a 1:1 mix of the two component Parts Part A and Part B. I got three of those Red Solo plastic cups. On the inside of two of the cups I marked a line the same height from the bottom, put Part A in one cup the line and Part B to the other in the other cup. Then I poured both into the third cup, mixed for the appropriate "Pot Time" then poured into the interior of the model.

Now, I only did that because my shop digital balance had died. See, the preferred method for mixing Epoxy Casting resins is to do the three cup method, but to do it by Weight, not volume. You put a cup on the balance, Tare, or "Zero" it out with the cup, add one part, take it off, put the next cup on, add the second part to the same weight, then mix in the third.

For some other Casting resins or polyester resins, Fiberglass Resin, you will have one part and a Hardener. Again, whatever product you buy should list the appropriate ratios of Resin to Hardener and you can use either volume or weight for that as well.
 

Coreforge

Member
Depending on the temperature, how well it was mixed and how exact the ratio was, epoxy can take a while. I've used epoxy with a 60 minute working time and a 24-48h cure time, but depending on how close I mixed it, it was sometimes still kinda flexible after a few days. It fully cured after maybe a week though, so try to just let it cure some more (I probably had a 1:1,5 ratio instead of the required 1:2 ratio, so it doesn't have to be super exact, but it might end up weaker, more briddle or more flexible if you get the ratio wrong).
 
This thread is more than 3 months old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.
Top