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oekmont
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Just puncture the bag on two opposite sides of the dry spot (near do the dry spot, but on the impregnated area. About an inch distance), and insert tubes just to the corner of the dry spot. Seal the tube/bag connection with tacky tape. Now run a second infusion, to catch up the dry area.
If you got a large dry patch, this means you got to much air in the system. Dry patches shrink until they reach atmospheric pressure, or the resin solidifies. Ideally they shrink to almost zero. If the area remains big, you might ask yourself where the air came from, to fill up big spaces under atmospheric pressure. There are two possibilities (If you bag itself is airtight)
-the pressure in the system not low enough when you starter the infusion
-your resin contained to much gas, which accumulated in one area wich was cut off from the vacuum line. Proper degassing would solve that, but I am talking against the wall with my opinion here at this forum.
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Hanaldo
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You can't hand laminate it, but you can reinfuse the part if you can remove the consumables without demoulding the part. If you manage it then you just replace the consumables and redo the infusion over the dry areas. But if the part pops out while you're pulling off the consumables then it won't work, as you'll get resin bleeding onto the surface of your part.
Did you warm up your resin at all?
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quinn
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First infusion was a fail. 90% of the part saturated in the first 10 minutes, then the dry spots just stopped shrinking. Resin continued to flow for another 20 minutes but it just took the easier path and went to the catch pot. I guess it was a mistake to try and do it without infusion resin. Looks like my 600cps epoxy just wasnt quite thin enoigh. Just ordered some infusion resin to give it another try. Unfortunately I had to buy 90 bucks worth, 1.33 gallons. Only need about 70g per canopy plus extra but for some reason infusion resin isn't available in smaller quantities like a quart.
Is there any way to salvage my 90% infused part? Right now it's still bagged and curing. Once it's cured, can I just pull the bag and wet out the dry areas through the flow media and peel ply? Or is it not likely to soak in and reach the surface?
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quinn
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+xOk, if its spray viscosity then it should spray through a 2.5mm. Might be a little slow. You can brush, but it's harder to get a consistent finish, so catalyze it slightly higher and keep an eye out for alligatoring. Molds came out great. I went with my original plan of using a split plug for laying up each individual half on a sheet of melamine. The method I used ensures a very nice joint between the molds. When milling the plugs I started with reference dowel holes on the back side. During the sanding and polishing of the duratec I had the 2 plug halves assembled together with dowel pins so the edges of the 2 halves meet together perfect for the whole seam. After laying up the molds on each plug half and popping them loose, I reassembled the plug halves back together, then placed the mold halves over the assembled plug and clamped the flanges together while trimming and drilling the mold flanges for locating pins. I did pairs of holes, one for a locating pin and one for a bolt next to it. I'm going to mill some short locating pins that have a flange on one side to make it convenient to pop them in there to reference the halves together. Probably let the mold cure another day and then lay up the first part  
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Hanaldo
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Ok, if its spray viscosity then it should spray through a 2.5mm. Might be a little slow. You can brush, but it's harder to get a consistent finish, so catalyze it slightly higher and keep an eye out for alligatoring.
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quinn
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+xDepends on if you're using a brush or spray viscosity tooling gelcoat. If you're using Unimould then its brush viscosity and it wont spray through a regular gun with a 2.5mm tip, you'd need a 5 or 6mm tip on a gelcoat cup gun. But yeh as you said, it doesnt matter. The only benefit to spraying over brushing is application speed, so it's great for big parts that will take a long time to brush up because you can spray it in 5 minutes. It's also slightly easier to get a consistent thickness, but if you've got a brush viscosity gelcoat then that shouldn't be a concern either. In any case, you shouldn't need to spray it for these pieces, it'll take 5 minutes to brush on. The gel coat I got is composite invisions brand orange tooling gel coat and is recommended to be sprayed so I'll give it a try. I'll have brushes ready in case I have trouble. Plug came out awesome, nice and shiny. Molds get layed up tomorrow
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Hanaldo
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Depends on if you're using a brush or spray viscosity tooling gelcoat. If you're using Unimould then its brush viscosity and it wont spray through a regular gun with a 2.5mm tip, you'd need a 5 or 6mm tip on a gelcoat cup gun.
But yeh as you said, it doesnt matter. The only benefit to spraying over brushing is application speed, so it's great for big parts that will take a long time to brush up because you can spray it in 5 minutes. It's also slightly easier to get a consistent thickness, but if you've got a brush viscosity gelcoat then that shouldn't be a concern either. In any case, you shouldn't need to spray it for these pieces, it'll take 5 minutes to brush on.
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quinn
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Plug is milled, sealed, and primed. Very slight orange peel in the duratec but knocks down flat very quickly with 300 grit. No pin holes or voids. Not bad for a 13 dollar spray gun and my first time shooting anything but laquer. Should be pulling molds friday.
So when I apply the tooling gel coat to the plug for first layer of mold, can I expect it to spray similar to the duratec primer? Or is it gonna be thicker and more difficult? My gun has a 2.5mm tip, but like I said it's a cheap gun. I suppose it's probably ok to brush it if I need to since it's just gonna lay flat on the plug. Surface finish before applying fiberglass layers shouldn't matter much I would think as long as there's a consistent build up that's thick enough.
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quinn
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+xDont worry about the gauge, they are all going to be inaccurate in one way or another. Some may be better calibrated than others, but at the end of the day the number they point to really doesn't matter. Keep in mind that elevation above sea level and atmospheric conditions will change the reading the gauge gives you as well. So one day it might read 26", the next day it could be 30mm past the 30" mark - and I promise you wont be pulling 32" of vacuum! Stick with what you've got. Your pump should be perfectly capable of pulling full vacuum, so if it goes quiet and stops emitting oil vapour when the gauge says you are at full vacuum then you are likely at full vacuum. If you're really worried about it, do some playing around and infuse some flat sheet. You'll learn a lot, and you'll also be able to look at the flat sheet and diagnose any problems - pump related problems are going to be obvious. you were right about the gauge. figured out an easy way to test the pump. room temperature water boils at 29.1 inches. put a few drops of water in the end of a tube hooked to the pump, capped it off and turned it on. boiled immediately. so now i know at least its hitting over 29, probably pretty close to full vac.
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quinn
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Group: Forum Members
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