New Builder - Paper Build Hardening Tips?

[Sylenn1537]

I was wondering if I could get some tips on hardening paper builds (cardstock 110lbs). After my last build, I tried the technique of hardening with fiberglass resin. Even with only applying a very thin layer, it's like the paper soaks up the liquid and the paper starts to deform / sag. I know you can put supports inside of the build, but on the suit I'm working on right now, that's not an option because of the very tight spaces you can't get into. I saw a Youtube video of someone using wood glue, but wouldn't this cause the same issue?

Thanks for the help!

 

[MoeSizzlac]

Are you applying it in small sections at a time?

Picture a helmet. It's best to mix up a small batch and work on different quadrants at a time.

In other words, mix up a small batch and only work on applying a light coat on the outside of the upper left quadrant (no fiberglass at this stage, just the resin). Then wait for it to fully dry and start with the outside bottom right quadrant. Continue until you have an entire light coat on the outside of your piece.

After the entire outside is done and hardened, then you can start on the inside but in a similar fashion as before (one quadrant at a time). This time, you can include fiberglass with your resin to give the pep piece even more structure.

It is also advisable to place the piece in a beneficial position while it hardens (i.e. leave a helmet upside down while the top parts harden and vice versa).

Let me know if this makes sense.

 

[Sylenn1537]

Are you applying it in small sections at a time?

Picture a helmet. It's best to mix up a small batch and work on different quadrants at a time.

In other words, mix up a small batch and only work on applying a light coat on the outside of the upper left quadrant (no fiberglass at this stage, just the resin). Then wait for it to fully dry and start with the outside bottom right quadrant. Continue until you have an entire light coat on the outside of your piece.

After the entire outside is done and hardened, then you can start on the inside but in a similar fashion as before (one quadrant at a time). This time, you can include fiberglass with your resin to give the pep piece even more structure.

It is also advisable to place the piece in a beneficial position while it hardens (i.e. leave a helmet upside down while the top parts harden and vice versa).

Let me know if this makes sense.

Thanks for the tip! I actually didn't try in small sections. The videos I have watched show them just coating the entire outside at the same time so that is what I did... The entire helm pretty much buckled in on itself lol

 

[MoeSizzlac]

Thanks for the tip! I actually didn't try in small sections. The videos I have watched show them just coating the entire outside at the same time so that is what I did... The entire helm pretty much buckled in on itself lol

Yep. That sounds like my first time. Pep work is long and tedious and looks great when done right. I think it is an important skill to learn along with foam working so don't give up on it just yet. I now concentrate mostly on 3D printing but I still reach back to these skills time and time again when working on my projects.

 

[dheighto]

One method is to "frame" your builds. Mix a small batch and coat only the joints, insides and out, about 1/ inch wide. Then let it set overnight before continuing.

You can test another idea on a test build: just build a small section, "frame" it, and spray coat with a matte finish clear coat or Dupli-Color Automotive Primer to see if the panels deform. The primer is like a spray-on plastic.

If the paper still absorbs and deforms, go ahead with the fabric/resin application and just coat depressions with a thin layer of Bondo and sand to suit. It's more work, but it allows you to shape your build better.

Might I also suggest using denim instead of fiberglass? I had problems with fiberglass unweaving and leaving dangerous spikes and protrusions of glass fibers. That required sanding which produced glass and resin dust - a problem I did not need. Denim is almost as strong and won't do that.

 

[he4thbar]

I coated the whole thing in like 2 batches. But I also used Popsicle sticks to give it a skeleton frame on the inside so it wouldn't come apart or fall in on itself.

 

[gknuth86]

I am also knew but I have found that if I coat my piece in sections with modgepodge it gives me strength and some water proofing so that when I resin/ rondo my pieces don’t crumble from being too wet