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Wet layup of fuel tank question

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Old 11-26-2012, 12:57 PM
  #1
mr_matt
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Default Wet layup of fuel tank question

Hi guys,

I am trying to make a large (1 gallon) kerosene tank. This is a one off, lost plug/mold job (whatever the proper terminology is)

I have the styrofoam shape and I covered it in kapton tape and wax. My plan is to glass over this with 2 layers of 2 ounce next to the plug (to minimize pin holes) then 2 layers of 6 ounce over that. After it cures I will saw it in half, remove the plug, add hardware, baffles, join it, etc etc.

My question is how to hold the glass down while it cures. My thought is to apply a final layer of teflon coated glass, then wrap the thing is ace bandages.

I have never done this before and I could get myself in a mess here so I am all ears.

Thanks in advance,


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Old 11-26-2012, 02:13 PM
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Default RE: Wet layup of fuel tank question

Quote:
ORIGINAL: mr_matt

Hi guys,

I am trying to make a large (1 gallon) kerosene tank. This is a one off, lost plug/mold job (whatever the proper terminology is)

I have the styrofoam shape and I covered it in kapton tape and wax. My plan is to glass over this with 2 layers of 2 ounce next to the plug (to minimize pin holes) then 2 layers of 6 ounce over that. After it cures I will saw it in half, remove the plug, add hardware, baffles, join it, etc etc.

My question is how to hold the glass down while it cures. My thought is to apply a final layer of teflon coated glass, then wrap the thing is ace bandages.

I have never done this before and I could get myself in a mess here so I am all ears.

Thanks in advance,


I have made several composite fuel cells over the years by the method you wish to make yours, I have even made them by cutting and folding cardboard to my desired shape and covering with teflon tape. I never did cut my tanks into two separate components in order to pull stuff from the inside, instead I located a spot on the tank for a service cover and mounted a robust stick in the master model; your foam plug is the master model and performed my layup repositioning the layup from the stick as I went. After full cure, in your case of styrofoam I simply poured acitone through the opening around the stick, the styrofoam completely melted away releasing the stick. Next I cut a 3.00" or 4.00" service hole around where the stick was and pulled all the tape, and flushed the inside really well with acitone. Now I had a tank with a hole, so I simply made an 60661-T6 aluminum ring with a slit in it and installed nut plates, I also drilled several rivet holes around the perimeter so I could install the ring on the inside of my tank by slipping it into the tank from the slit in my ring, once the ring was riveted in place I was able to make a matching plate that screwed on from the outside picking up the nut plates on the ring mounted on the inside. This plate was also made of 6061-T6 aluminum so that made it weldable for my fuel caps assemly, fuel pickup lines, or whatever. Once everything was completed on the tank I would pour MEK in side the tank slosh it around pour out and repeat 3 times. Next I would pour in tank sealer from Aircraft Spruce & Specialty, seal up, slosh around, the sealer builds pressure and forces itself into the porosity of the composite tank during this process and seals the tank. Next open and dump all tank sealer back into the sealer can and allowed the tank to sit open overnight dripping onto something you can discard later, I always repeated the sealer application the next day and the tank was sealed and ready for use.

Here is a picture of a 2.5 gallon tank I built for one of my R/C models nearly 13 years ago, built the way I explained in this post, and still holding gasoline with no issues.

Bob
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Old 11-26-2012, 04:36 PM
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Default RE: Wet layup of fuel tank question

Sounds great but what did you cover the outside with while it cured? Peel ply of some sort?
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Old 11-26-2012, 05:08 PM
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Default RE: Wet layup of fuel tank question

I just did the layup and allowed it to cure on its own, I never cover the layup with anything, now I did as always layup everything with epoxy, for me it's the only way to go.

Bob
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Old 11-29-2012, 06:58 AM
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Default RE: Wet layup of fuel tank question

Try plastic cling wrap on the outside. Like the stuff used when moving pallets. Assorted size rolls. Don"t even have to remove it.

Steve
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Old 11-29-2012, 08:07 AM
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Default RE: Wet layup of fuel tank question

Matt, I would just bag it with peel and ply as the wrap. You can even just use wax paper over that if you like so the breather felt and bag doesnt get stuck to it. There may be a bit of epoxy leaching out any ways but no big deal. You will have a little bit to sand at the seams and areas that have the unavoidable crease, but peel and ply leaves a decent finish.
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Old 11-29-2012, 11:25 AM
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Default RE: Wet layup of fuel tank question

What is the purpose of wrapping your layup with peel ply or handy wrap? Is it just to make it look better or an effort to seal the tank from leaks?

Bob
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Old 11-29-2012, 03:13 PM
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Default RE: Wet layup of fuel tank question

better structural density and reduction of voids
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Old 11-29-2012, 04:49 PM
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Default RE: Wet layup of fuel tank question

The consolidation of the laminate by debulking through a perforated release media into a blotter and removing excess resins would give the reduction in porosity and the structural quality you speak of, as well as a thin lightweight layup. Just wrapping a layup in handy wrap or placing in a plastic bag won't do that for you because the moment the resin soaks through and this bag and gets wet even if there was vacuum; it would no longer have an airway to pull any vacuum. In addition none of this will it keep fuel from finding it's way though the porosity, it will still need to be sealed from the IML.

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Old 11-30-2012, 07:34 AM
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Default RE: Wet layup of fuel tank question


[quote]ORIGINAL: sensei

The consolidation of the laminate by debulking through a perforated release media into a blotter and removing excess resins would give the reduction in porosity and the structural quality you speak of, as well as a thin lightweight layup. Just wrapping a layup in handy wrap or placing in a plastic bag won't do that for you because the moment the resin soaks through and this bag and gets wet even if there was vacuum; it would no longer have an airway to pull any vacuum. In addition none of this will it keep fuel from finding it's way though the porosity, it will still need to be sealed from the IML.

Bob
[/quote

I think the weight issue would be nominal. Grams maybe. The ability for the tank to be leak free would depend on the treatment of the first layer.

For what Mr. Matt is trying to accomplish, the cling wrap has a good chance of working without the cost of vacuum bagging.

Steve
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Old 11-30-2012, 08:27 AM
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Default RE: Wet layup of fuel tank question

[quote]ORIGINAL: SCALECRAFT


Quote:
ORIGINAL: sensei

The consolidation of the laminate by debulking through a perforated release media into a blotter and removing excess resins would give the reduction in porosity and the structural quality you speak of, as well as a thin lightweight layup. Just wrapping a layup in handy wrap or placing in a plastic bag won't do that for you because the moment the resin soaks through and this bag and gets wet even if there was vacuum; it would no longer have an airway to pull any vacuum. In addition none of this will it keep fuel from finding it's way though the porosity, it will still need to be sealed from the IML.

Bob
[/quote

I think the weight issue would be nominal. Grams maybe. The ability for the tank to be leak free would depend on the treatment of the first layer.

For what Mr. Matt is trying to accomplish, the cling wrap has a good chance of working without the cost of vacuum bagging.

Steve
So you are stating a resin rich wet layup overall is almost the same weight as a controlled flow bag system layup, that is not nearly true, and the first ply of cloth down even as a pre-preg system will in no way insure that you will have a 100% porosity free and fuel proof tank, only slush coating the IML will do that for you. I head up a aerospace composite manufacturing company and several of the products we manufacture and assemble require slush sealing after assembly because we simply cannot leave it to chance then warranty our product without this process. On a side note, most all the product we sell are weight critical to our customers and I have spent nearly 40 years designing and developing composite and other substrate structures and ways to manufacture the lightest weight possible... So for what Mr. Matt is trying to accomplish with a one off is to just lay it up as I already stated and slush coat it. This way he doesn't need to leave it to chance that maybe it will work out.

Bob
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Old 11-30-2012, 02:11 PM
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Default RE: Wet layup of fuel tank question

With all due respect.

You are correct that vacuum infusion would be lighter. But not an issue for this specific application.

Only in this R/C specific application, the few grams/ounces will not make or break this specific project. In a large piece it may.

Leakage. I would guess that this is a vented tank for turbines, it would hold fluid if the resins used are not dissolved by the fluid it contains.

Kinda like a glass boat hull, only that keep fluid out. Especially a thin R/C boat hull, free hand layup no leaks or permeation..

In your field I'm sure the specs, sizes, and pressures are much more demanding.

Steve
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Old 11-30-2012, 02:44 PM
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Default RE: Wet layup of fuel tank question

Grams turn to ozs. and ozs. to lbs. weight is very important in our R/C models especially the smaller ones. Thin laminate fuel tanks will have some porosity, it is the nature of the beast and vented or not fuel will find its way through. We do this in full scale application without a second thought, to me anything worth doing is worth going the distance and doing right.

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Old 11-30-2012, 08:47 PM
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Default RE: Wet layup of fuel tank question


Quote:
ORIGINAL: mr_matt

Hi guys,

I am trying to make a large (1 gallon) kerosene tank. This is a one off, lost plug/mold job (whatever the proper terminology is)

I have the styrofoam shape and I covered it in kapton tape and wax. My plan is to glass over this with 2 layers of 2 ounce next to the plug (to minimize pin holes) then 2 layers of 6 ounce over that. After it cures I will saw it in half, remove the plug, add hardware, baffles, join it, etc etc.

My question is how to hold the glass down while it cures. My thought is to apply a final layer of teflon coated glass, then wrap the thing is ace bandages.

I have never done this before and I could get myself in a mess here so I am all ears.

Thanks in advance,


Bob, Mr. Matt's original question was "how to hold down the glass". My answer was directed mostly at that issue for this application.

However, I do agree that grams turn to ounces and lbs and ect....... But not in this specific case.

Either way, I hope our discussion will help Mr. Matt solve his problem.


Steve
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Old 11-30-2012, 08:48 PM
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Default RE: Wet layup of fuel tank question


Quote:
ORIGINAL: SCALECRAFT


Quote:
ORIGINAL: mr_matt

Hi guys,

I am trying to make a large (1 gallon) kerosene tank. This is a one off, lost plug/mold job (whatever the proper terminology is)

I have the styrofoam shape and I covered it in kapton tape and wax. My plan is to glass over this with 2 layers of 2 ounce next to the plug (to minimize pin holes) then 2 layers of 6 ounce over that. After it cures I will saw it in half, remove the plug, add hardware, baffles, join it, etc etc.

My question is how to hold the glass down while it cures. My thought is to apply a final layer of teflon coated glass, then wrap the thing is ace bandages.

I have never done this before and I could get myself in a mess here so I am all ears.

Thanks in advance,


Bob, Mr. Matt's original question was ''how to hold down the glass''. My answer was directed mostly at that issue for this application.

However, I do agree that grams turn to ounces and lbs and ect....... But not the primary issue in this specific case.

Either way, I hope our discussion will help Mr. Matt solve his problem.


Steve
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Old 11-30-2012, 09:10 PM
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Default RE: Wet layup of fuel tank question


Quote:
ORIGINAL: SCALECRAFT


Quote:
ORIGINAL: mr_matt

Hi guys,

I am trying to make a large (1 gallon) kerosene tank. This is a one off, lost plug/mold job (whatever the proper terminology is)

I have the styrofoam shape and I covered it in kapton tape and wax. My plan is to glass over this with 2 layers of 2 ounce next to the plug (to minimize pin holes) then 2 layers of 6 ounce over that. After it cures I will saw it in half, remove the plug, add hardware, baffles, join it, etc etc.

My question is how to hold the glass down while it cures. My thought is to apply a final layer of teflon coated glass, then wrap the thing is ace bandages.

I have never done this before and I could get myself in a mess here so I am all ears.

Thanks in advance,


Bob, Mr. Matt's original question was ''how to hold down the glass''. My answer was directed mostly at that issue for this application.

However, I do agree that grams turn to ounces and lbs and ect....... But not in this specific case.

Either way, I hope our discussion will help Mr. Matt solve his problem.


Steve
Sounds great Steve. By the way, looks like your doing a great job on your Star Fighter...

Bob
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Old 12-01-2012, 12:14 PM
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Default RE: Wet layup of fuel tank question

Thanks Bob.

I bet I can get the composite Starfghter fuse to hold water.

Sorry Bob, had to.


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Old 12-01-2012, 02:30 PM
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Default RE: Wet layup of fuel tank question

Quote:
ORIGINAL: SCALECRAFT

Thanks Bob.

I bet I can get the composite Starfghter fuse to hold water.

Sorry Bob, had to.


Steve
LOL, it's all good brother.

Bob
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