Custom Fiberglass Extended Swim Platform

[tpenfield]

Nice, I could have used a vacuum of that sort with all the sanding I have done. . . dust is everywhere Did I mention that I hate sanding . . . I also put grinding (fiberglass) in that category too.

I found an article pertaining to my latest thought process . . . it is called "Dynamic Pressure Control in VARTM" .

I'm not able to access the complete article, but the intro talks about reducing the vacuum pressure during resin infusion to speed up the flow of resin into the fiber. Then once the resin is injected, resume the high levels of vacuum to saturate the part. Resin infusion times are cut in half and there are improvements to the resulting part. I'm all in, if that be the case.

I'm going to see if I can get access to the full article.

 

[kcassells]

http://www.advancedprocess.com/vartm-vacuum-assisted-resin-transfer-molding/

 

[mickyryan]

I have one of these - twin 4" inlets that will suck the wings off an eagle lol

reminds me of a a gal i once knew her problem was she chased too many eagles

 

[Mad Props]

:faint2::faint2::faint2::faint2::faint2:

Ted, I had no idea you were using a shop vac as a vacuum source... When I first read the post, I thought you were joking lol. A shop vac isn't going to pull nearly enough vacuum to pull resin through the mold.

A job like this is going to require an actual vacuum pump or the alternative would be a vacuum generator (This is what I use for my vacuum press for wood veneering). It uses your air compressor to create a vacuum, I know, sounds like black magic lol. Its basically a big venturi valve and as long as you have a respectable size compressor, it will pull nearly the same amount of vacuum as a pump. I can get down to 27 or 28 inHg. They can be had on ebay for like 30 bucks.

 

[tpenfield]

Yes. . . Guilty as charged

I figured for the small parts, like the hatches, a partial vacuum would be OK, and it was. For the main platform, I have a vacuum pump on order.

I'm thinking of using my compressor to give the resin pots a little 'boost' during the infusion.

 

[dezmond]

I found a vacuum pump that has very good ratings and seems to pull about 25-30 Hg according to the reviews. It seems to fall within the spec's recommended on the fiberglass web sites, in terms of capacity, etc. for this size of job.



I have this pump, some extra oil, and a gauge on order for around $110 . So, it seems worth it to get this for the project.

This should be a lot better vacuum, and give the shop vac a rest

Thanks fishrdan for the suggestion.

I use one of these when I am stabilizing knife handle scales. It works great pulling the resin into the punky wood.. Never had any issues. Just watch oil mist coming out of the little exhaust thingy. I put my pump outside as I don;t like everything having a small oil film on it. Aaaaaand you with working with fiberglass, gel, etc. You won't want that on your stuff either.

 

[Grub54891]

I use one of these when I am stabilizing knife handle scales. It works great pulling the resin into the punky wood.. Never had any issues. Just watch oil mist coming out of the little exhaust thingy. I put my pump outside as I don;t like everything having a small oil film on it. Aaaaaand you with working with fiberglass, gel, etc. You won't want that on your stuff either.

Good point. I attached a hose to the outlet, put the hose into a coffee can, and put an oil sorb pad in the can also to filter out the mist works good.

 

[tpenfield]

I have been searching the internet for information regarding improving the fill time on the vacuum infusion process. So far, I have not come across anyone/anything that talks about using a pressurized resin pot to inject the resin at a faster rate. Not sure why, it would seem like a viable option when reducing fill time is important.

I have found some articles about adjusting the vacuum pressure during the fill (less vacuum) and then increasing it once filled.

At this point I have a collection of ideas . . .

1) pressurize the resin pot (as mentioned) . . . Pressurized resin pot seems to be an RTM process and drawing resin from the pot via vacuum seems to be a VARTM process, but I have not seen the 2 mixed in any experimentation.

2) slight thinning of the resin

3) slight cooling of the resin to delay reaction time (55 F)

4) reduce vacuum during fill, so the resin can flow outward from the runners more rapidly. Then increase to full vacuum once the fill is complete, which will tend to flatten the resin out, forcing it through the fiberglass.

5) lots of runners, creating a large discharge area throughout the mold.

Any other ideas? :noidea:

I have a viscosity tester on order, so I can check the viscosity of the resin and the effects of temperature reduction and/or thinning.

I think I'm also going to set up a 2 sq.. ft. test piece to see if I can get some timing and resulting quality of process indications.

 

[tpenfield]

Quick Update:

I have posted my 'rapid fill' question on a fiberglass/composite forum just to see what comments I get from folks who do this stuff at a higher level.

One comment that has come back was to 'slow down' the resin gel time using an 'inhibitor' . . . . Brilliant !!! I didn't even think of that. What's an inhibitor :noidea: . . . beyond the obvious, that is.

So, I could come at this problem from either direction . . . increase the speed of the resin . . . or . . . slow down the gel time of the resin. It looks like I could get the resin to stay workable for 2-3 X the standard time, which is only about 20 minutes, using an inhibitor.

If the resin would remain in a 'flow-able' state for 40-60 minutes, then I think I can forgo the pressure pot idea and just use gravity flow to facilitate matters. My preference is to slow the gel time down, as that will allow the resin more time to work its way through the peel ply and into the layers of fabric.

Of course, poly resin inhibitors are not exactly an off-the shelf item, so I'm having to dig a bit deeper. But at least the fog is clearing and I can see a path forward :thumb:

Next step is going to be to set up a test of the infusion/vacuum and resin flow, then do some timing of the resin flow and how well it soaks into the fiberglass, etc.

Boxes of stuff keep arriving on a daily basis and I continue to order bits and pieces of what I will need. I should have the vacuum pump today.

I'm heading to the boat show later this afternoon. If I see a ready made swim platform there, I just might buy it

 

[kcassells]

Lot's of to do on this learning curve. All Good as usual! Laugh my butt off if you come home with a swim platform.

 

[tpenfield]

No swim platforms to be had at the boat show. I did take a look at a Formula 310SS with the twin Ilmor engines and outdrives . . . $344K :faint2:

I guess I got to keep going on this swim platform project

 

[Mad Props]

I wish I could give you more advice on this stuff but it's out of my wheelhouse... I watched a bunch of youtube videos thinking I'd learn something, but they all seem to show the resin transfer being REALLY slow... so maybe there is no magic trick other than using low viscosity resin, keep it cool, and mix it with min mekp... other than that, good luck lol..
I was wondering if a more aggressive breather cloth would help the resin get thru the mold faster...

 

[tpenfield]

I think if I can figure out an 'inhibitor' for the resin and slow the gel time to 40-60 minutes, as well as do the other things, then it should be OK. Anybody heard of . . . 4-tert-Butylcatechol (TBC) . . . :noidea:

There is a product called 'Pergaslow BK-10', which is a 10% TBC solution, used to slow the gel time of resins. . . It only seems to be sold in Germany though. I could not find it available nor an equivalent from a USA based supplier. :facepalm:

I am going to run a test piece next weekend with a small amount of thinning and cool resin, then time the speed that the resin travels across the test piece. If I can get some inhibitor in the meantime, I'll include that in the test.

 

[oldrem]

Try contacting the US office PERGAN Marshall LLC
710 Bussey Rd Marshall, TX 75670 USA
Tel.: +1 903-938-5141

 

[Mad Props]

This is where we could REALLY use ondarvr but I haven't seen him post in quite some time.

 

[tpenfield]

This is where we could REALLY use ondarvr but I haven't seen him post in quite some time.

I am in conversation with him over on another forum.

He has steered me towards a catalyst that also extends the gel time, rather than doing it with an inhibitor.

 

[tpenfield]

Try contacting the US office PERGAN Marshall LLC
710 Bussey Rd Marshall, TX 75670 USA
Tel.: +1 903-938-5141

Thank you . . . :thumb:

I don't know why I was not able to find it as I have been searching over the past couple of days. I sent them an inquiry just now.

 

[tpenfield]

In other news . . .

I tested the new vacuum pump. It pulls about 28 Hg :thumb:

 

[chevymaher]

Once it pulls that let it sit and boil off the liquids. Then run it again and you may get 29.5 if your lucky. There is no perfect vacuum.

 

[Mad Props]

There is no perfect vacuum.

Not with THAT attitude...


not sure you need absolute perfection but its gonna do worlds better than a shop vac haha...
I bet that thing would sound normal till it sucked down and then wind up to a pretty good whistle lol

p.s. glad to hear ondarvr is still around, he is a wealth of knowledge...