Custom Fiberglass Extended Swim Platform

[Scott Danforth]

. . . otherwise, I think I would have ended up with clutter and overkill.

remember....there is no load like an over-load.

 

[Ciera2450]

Amazing work on the plug!

 

[tpenfield]

Thanks guys . . . :thumb:

I made the drive out to Springfield MA to pick up the fiberglass & resin stuff. Basically, it is a 1 man operations called Merton's. It seems like he is one of only a handful of fiberglass supply houses within a 2-3 hour drive of Boston.

I saved about $200 in shipping versus some of the other sources that I have been using.

Anyway, I have been waxing the plugs . . . over and over . . . I'm on the 6th coat of wax, which is what is recommended.

Then I will coat the non-skid areas with PVA (polyvinyl alcohol) as its mold release agent.

I probably will be setting up to infuse the hatch molds later today or tomorrow. Just don't want to get ahead of myself and forget something.

 

[tpenfield]

Quick update . . .

It tried the vacuum infusion on one of the ladder hatches as 'practice' . . . hopefully useful practice.

Well it looks like I got to keep the day job, because it was an epic fail :facepalm:

Everything started off OK, but things went downhill once I started to infuse the resin.

Here are a few photos . . .

Gelcoat went on fine . . . I used 1.5% MEKP, but probably 2% would have been better. I had to put some extra heat on it to get it to kick.


So, after a few minutes, I stopped the vacuum, opened up the bagging and dumped the rest of the resin, worked it in a bit, then re-sealed the bag and went to straight vacuum bagging. This worked out better, but the resin had started to kick by then, and as a result, there is a void in one area.

I'll see how things look once it is all cured, but this one may take another try. Next time, I probably will feed the resin from the top/center and pull the vacuum from the perimeter, to see if that works better. Basically opposite of what I had set up for this 'practice' round. Also got to use the breather cloth around more of the part.

 

[Ciera2450]

Forgive my non expertise... couldn’t you just lay up over? Versus vacuum bagging... I know the benefits of the latter but what made your decision his way? I ask, because I’ll soon be attempting similar. Albeit, nowhere near the craftsmanship.

 

[tpenfield]

Forgive my non expertise... couldn’t you just lay up over? Versus vacuum bagging... I know the benefits of the latter but what made your decision his way? I ask, because I’ll soon be attempting similar. Albeit, nowhere near the craftsmanship.

I wanted to have the fiberglass as tight to the plug as possible considering the molded in non-skid pattern. That is why I chose to use vacuum bagging & infusion rather than hand layup.

 

[tpenfield]

I decided to remove my 'failed' mold attempt from the plug, considering that I may need to re-do it. Well easier said than done . . . It took all of my wedges and a few other tools to pry the mold off of the plug.

Bad news is that the plug took some damage in separating the mold from it . . .




I used PVA on the non-skid pattern, but only used the release wax on the rest of the plug. I'm thinking maybe PVA on the rest of the plug for the other ladder hatch.

So, not quite the failure I had originally thought.

Tomorrow, I'll try the other hatch.

 

[sphelps]

I would call that a win with a bit of learning experience mixed in !

 

[kcassells]

Ted,
Thanks for the details and pics. Looks like you're having fun.

 

[tpenfield]

OK, round 2 today . . . and as sphelps said, with a bit of learning.

Learnings from yesterday.

- Feed resin to the middle/high point of the part, let the vacuum pull the resin to the perimeter.

- PVA on the sides of the plug. . . the sides of the hatches are not well tapered, because of how the actual part needs to fit in the platform opening. So, the sides of the mold had a bit of a death drip on the plug. (The platform plug has much more taper to the surfaces)

- Let the gelcoat set up a little bit more before doing the laminates

- I did not use 'peel ply' on the first practice, so I will use peel ply this time.

- Less 24 oz WR. . . it seemed to be difficult to form around the curves of the plug.

- More breather cloth

Hoping it cannot be any worse than the first attempt.

 

[Scott Danforth]

Ted, spray liberal amounts of PVA as a mold release. use an HVLP gun

 

[oldrem]

We have faith in you. It'll be dang near perfect when you're done.

 

[tpenfield]

Sunday afternoon update.

Ladder Hatch mold #2 . . .

Success . . . at least much better.

I put down 2 layers of CSM, then a partial layer of 24 oz WR, then peel ply. The resin was fed under the peel ply.

The resin flowed pretty well, but I did coax it along with a roller. Here are a few pictures of the infusion.

The resin staring to flow


After about 5 minutes . . .
The plug also survived . . .



This mold does not need much in the way of touch up. The non-skid pattern is great.

One thing that I am realizing, is that the resin does not flow very far before it starts to set up . . . Maybe 10-12" at the most after about 20 minutes.

Maybe I should consider thinning the resin by about 5%, but I'm not sure how that will affect the curing process under vacuum. :noidea:

I've also considered cooling the resin down, but that may also slow down the flow.

One thing that I am not quite understanding is that the gelcoat (orange) is not fully curing. I wonder if the resin has something to do with that :noidea: I waited until the resin became hard, but not fully cured. Maybe I should let the gelcoat cure more???

I'll be doing the platform mold in a couple of weeks (maybe). One thing for sure, is based on these 2 practice runs, I need to be sure to feed the resin at many locations.

 

[Scott Danforth]

I know in spraying gel, they recommend to ice the gel and duratec for about 20 minutes to extend the time before it kicks to 15 minutes

 

[tpenfield]

I know in spraying gel, they recommend to ice the gel and duratec for about 20 minutes to extend the time before it kicks to 15 minutes

Maybe worth a try then. . .

 

[tpenfield]

Trying to work through a couple of issues . . .

First is that the tooling gelcoat does not seem to be curing properly. Note the traces of gelcoat left on the plug. The gelcoat in the mold is a bit tacky and seems to remain so. I am letting it set-up.cure for about 90 minutes, then doing the infusion of resin.

The resin is an "orthophthalic" poly resin, whereas the tooling gelcoat is described as typically being used with "isophthalic" resin. No specifics about the gelcoat itself. I'm not sure of 'ortho' vs 'iso' :noidea:

The second thing is the infusion plan for the platform itself. I am figuring on lots and lots of 'runner' of the resin to quickly flow to all areas of the mold. Here is the plan for resin runners. There will be 5 (five) 1/2" tubes connected to the runner system as shown. Vacuum will be taken from the perimeter, which is the method that seemed to work best with the hatch molds.


I am hoping this setup, along with some coaxing via a resin roller will be enough to quickly flow the resin (about 3or 4 gallons) to the mold. No good way to test it though . . .

 

[oldrem]

Not sure if any metal casting techniques would work on resin, but we always fed the thickest sections first forcing material into the thinner areas where we had sacrificial "overflows" to insure a good fill. However, my experience is primarily high pressure high volume aluminum and zinc casting.

 

[kcassells]

Ted...This is a total whole nother learning curve for me. Very interesting to say the least. Only pulling for ya to knock it out. And you will.

 

[froggy1150]

I know nothing...... that said what about also having resin fed from a pressure tank? A little push to help speed up the pull..... Probably a dumb idea:noidea:

 

[tpenfield]

Thanks guys :thumb: I am doing a bit of catching up on 'resin viscosity' and 'rheology' (which I didn't even know as a word until now )

Anyway, . . . Note to self: pay more attention to resin viscosity specs going forward. Thinner (lower viscosity) resins work better with infusion techniques. Of course, I knew that going in. . . but did not give it too much consideration in sourcing the resin.

What I have is medium viscosity resin, which is OK, but not great. I think I can compensate with a slight bit of thinning (like about 3%) and promoting the flow into the mold ( lots of resin runners, gravity feed, etc. ) I'm also thinking if I could put a bit a pressure into the resin pot . . . :noidea:

Polyester resin is the most difficult to work with IMO, because it begins to cure so quickly. Yesterday, on my second trial run making the second ladder hatch mold, the resin stopped flowing after a while, which then I realized that it was gelling in the pot and tube. That is why I don't like to use poly resin and have preferred VE or EEEEpoxy in my prior projects.

I can probably compensate for the quick curing of Poly by lowering the resin temp to about 50 F and keeping the catalyst a tad below 1.5%

I have also come to realize that gelcoats need at least 2% catalyst, otherwise it sits there and laughs at you.

My working temperatures have been in the 68 F degree range, but I have been able to put the small molds in my utility room where the furnace is located, which is about 80 F.

The actual parts that will be made from the molds are going to be VE resin, which in my experience has about 45 minutes open time, vs. 15-20 mins of poly resin. VE is better at stress and strain than poly resin BTW . . . which will be important for the swim platform.

Anyway, it is a good thing that I started small with the hatch molds, as it has given me some real-life experience with resin flow.

At the end of the day, I'm still thinking infusion is the way to go, as I don't see myself doing hand layup of 40 +/- square feet of CSM and/or 1708 in any efficient manner. My thinking is that its better to get the resin into the mat/cloth all in one shot, then use a resin roller to push the resin around as needed.