I'm looking for a better fuel proof sealant. Due to space restrictions and complexity of the supercharger/intercooler installation the plenum, that receives compressed and intercooled air before guiding it to the intake ports, had to be assembled from several pieces. I've got O-rings and O-ring string sealing most of the assembly but I've got leaks in the lower corners of the rectangular (shoe box shaped) plenum. I knew this would be a problem when I built it but assumed (wrongly) that I would be able to plug up the corners with gas tank sealer. Apparently the reversion fuel spray is collecting in the corners of the plenum, somehow softening the gas tank sealer and then the boost pressure is finding a way to open up the corners. It's not a problem at speed but at idle when the plenum is under vacuum I'm getting just enough false air to raise the idle to an annoying level. We're talking 4 small leaks here. Welding is out of the question since I need to be able to disassemble the plenum to remove it. I've considered JB-Weld epoxy since the label says it can be used on fuel tank leaks but if you read the fine print it says that it's water PROOF and fuel RESISTANT. Thats not the same thing in my book. Hylomar stays deformable so that's no good. I'm considering Wurth Orange Flange Sealer and Ashland Pliobond Industrial Adhesive which are at least fuel resistant but I haven't been able to find any good technical buletins to nail down what is absolutely fuel PROOF! Anyone know what is used to bond race car fuel cells together? Do any of you guys know of an absolutely fuel broof, solid setting sealer?
Sounds like you need to back to the drawing board and fix those corners for sealing and flow work. However, I'd try Dow Corning 730. The Orange loctite anarobic flange sealent may not be pliable enough. It's expensive, but it is made specifically for oil and gas and temp. Its primary use is for sealing non gasket surfaces, but I use it in many applications throughout motor and gear box. I've never had any luck with o-ring "string" the kit to make an o-ring. Try and find the total perimeter distance and find a solid o-ring to fit.
I have had good luck with two items MSC sells a Fluropolymer silicone type sealant. It is white, and about $60 a tube. POR 15 http://www.por15.com/ sells a few things to seal fuel tanks. The thickend one in a tube may work for you. It makes a very strong bond, so be careful if you may have to dissasemble the part.
Thanks for the input but going "back to the drawing board" is an option I'm trying to avoid. We have a giant O-ring selection but occasionally still wind up making odd size O-rings from rubber string with success. In this case I didn't use it to make rings though. The plenum components have grooves machined along their lengths and around the perimeters of the end panel faces with long lengths of O-ring string stuffed in them as seals. This works well except in the 4 lower corners where the long O-ring strings end. I know I can machine a new bottom panel but before doing that I'd like to find an easier way out! I'll look into the Dow Corning730. Thank you.
Thanks, I'll check into those 2 products. I was looking through my MSC catalog but didn't see the fluropolymer sealant! I just need a little dab in each corner so if i need to jack-hammer it out later it won't be too bad.
I looked it up in MSC, so we have a second vote on DC #730. I have used this to seal fuel senders on the bottom of MC tanks. Works well, but is pricey, looks like it is up to about 70 a tube They also list a GE product ( FRV 1106) at about 110 per tube. I have used Urethane sealants in the past, but the Ethanol they now put in fuel attacks it.
I checked my 2006/2007 MSC catalog and their on-line catalog and can not find DC750. All I find are silicone sealants and some very expensive high and low temp grease products made by Dow Corning. Can you give me a page number?
i would try the aircraft liquid sealers. we have a variety of different ones we use, and all of them are flexable, fuel proof and easy to work with. ill see if i can get the manufactures names for you. i cannot post Gulfstream part numbers on the net, and thats what i know them by off the top of my head. i think one manufacturer is SEM-KIT, a 2 part mixable sealant that is fast curing and seals higher pressure internal structures. there is a French chemical company called Courtalds, and another called Mastinox. (yellow Mastinox is an anti corrosive lube and is EXTREMELY toxic. i would avoid using it on any car parts)
Hello fellow 77 308GTB owner! I don't know why I didn't think about aircraft in my search, thank you. I just looked in my Aircraft Spruce catalog (a supply source for home aircraft builders). Anyway, they have several fuel tank sealers but aviation gas probably doesn't have some of the recent aditives automobile fuel has gained. ?? They sell a "two part polysulfide integral fuel tank and fuselage sealant" which they claim has "excellent resistance to oils,solvents, all fuels" "B-2 type material, meetsspecification MIL-S-8802E, Type II, Class B2. It comes in a 2oz or 3-1/2 oz cartriges. Gun is sold separately. I'm still not thrilled with the word "resistance" when it comes to compatibility with fuel. Since you are in the aviation business, do you know if the above MIL SPEC will cover me? Do you know of a good source to purchase the chemicals you posted?
PRC 1422 is what we used in fuel tanks of commercial jet aircraft. Its a 2 part epoxy with variable work times. It has a FAA dated shelf life so if you can find an expired kit you can get it almost for free, although I still have used it effectively several years past expiration.
I would do a internet search. Here in Dallas, which seems to be the aviation capital of the world, there are aircraft supply houses which carry it. Look in your yellow pages under Aircraft/aviation supplies. Like I said, look around for expired kits which can be had cheap. They are considered to be garbage for aviation use.
Loctite 515 flange sealer will do what you are looking for. It is fuel, oil, and coolant proof and reasonably priced at about $14 a tube. Most industrial supply houses should have it. I purchase through Enco. I use 515 on multi piece intake manifolds and to seal both wet and dry cylinder liners to block castings I resleeve. Steve
hi, B-2 MIL 8802 IS WHAT WE USE the gun is a regular chaulk gun, you can use the ratcheting ones, we use air sealant guns. i just removed a pair of wings from a customers Gulfstream GIII for repairs to the BL-6 main sparrs. it was a big project, and we resealed everything per the manual with B2/8802. this is good stuff! PRO SEAL makes aircraft sealant also. the best stuff comes frozen and has a 4-6 hour working life. there is a PR1440 i think made (by Pro Seal) that is a 2 part mixed sealer that you can inject out of a sealer tip and it works great for intake gasket fay seals *cough* i have no clue what the stuff costs, but when its expired for aircraft use we toss it, so you should be able to get out of date stuff for automotive use. wear gloves to protect your hands, and dont let pets or children come in contact with any wet sealer or tools. the stuff is not *that* toxic, but its not good for you. also, avoid the *890* class sealers, they are not fuel rated ( at least for out aircraft) and are more for corrosion resistance and pressure sealing. they are heavy with chromates and very toxic. i am only adding this so you dont get a bunch of free stuff from some airport and have a problem . sorry for the long novel, i dont get to talk much about what i do for General Dynamics. pm me if you need any help. i do know i can NOT help get any used sealer though. our security and the paperwork is too much of a headache with all the 9/11 measures in place. i will be glad to help with any sealer advice though!
Wil, without seeing the surfaces you actually trying to seal, I would tend to agree with the aircraft type flexible epoxies Mike and David are suggesting. I recall using some 3032? Mike you might know what I am refering to. It was almost black when mixed. I made patches to seal the wing roots from airflow on an old AeroCommander. The stuff was stipled into fiberglass mat in two layers or "plys" and when it cured it was like I had made a section of rubber fabric. Absolutely amazing stuff. One other suggestion would be two stroke engine case sealant. I bought some stuff made in sweden from a Stihl chainsaw dealer, and that stuff is real good too. Its everything proof.
http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1656577&PMT4NO=15393274 page 2611 of my 2005/2006 catalog
yes, there are sealants made by a division of PPG that have an activator in the "stick" that you press in and then mix the stuff up. the color change is to ensure a proper mix, as ANY white or gray streaking means the stuff is not mixed and it wont cure. when its black , it will cure very fast, depending on which system it is. by the way, if you guys dont have the mixer, you can use and air drill and a conical rotary file that will fit into the base where the 2 small holes are and really MIX IT well !
515 & 518 (slightly flexable) are also sold by most auto parts places as Permatex 515 or 518. It's an Methacrylate ester anaerobic sealant, won't set up if you just spread it on a surface open to the air. But will seal gaps up to something like 0.030-0.050. Probably would seal larger gaps if you put a strip of tape on each side to keep air out while curing. Tech data sheet: http://tds.loctite.com/tds5/docs/515-EN.PDF
When it comes to picking sealants, remember that like dissolves like. This is why petroleum based sealants won't work in a petroleum system. The best way to patch a gas tank, in a hurry, is with a bar of ivory soap. Rub it over the leak, it will plug the hole. Check patch integrity with the Zippo method. (wink) -or- buy some non-petroleum based stuff.
Thank you. I'll look into those and may have used them already for other purposes. The problem is I already have a good quality German anaerobic flange sealer but the fine print says that it is "fuel resistant" not fuel PROOF. I'm not eager to keep taking this appart again. The other problem is that the flange sealer I have turns to concrete. In most cases this is good but it's going to really complicate disassembleyin this case. The ideal would be an RTV silicone type caulking bead that could eventually be scraped away to then allow normal dissembly without damaging delicate parts. Unfortunately RTV silicone is not generally fuel proof. I'm hoping one of the aircraft sealants others have mentioned will do what I need.
PRC is a division of Courtaulds Aerospace. 920 Ave R Ste 200 Grand Prarie TX 75050 I would get the pint kit as opposed to a tube. The can you can use what you need and keep the rest for later, the tube is a one shot deal. PR 1422 B 2 is what I would use. This info may be updated or an alternative may be available.(my can lists 1998 as mfg date).
PRC is a division of Courtaulds Aerospace. 920 Ave R Ste 200 Grand Prarie TX 75050 I would get the pint kit as opposed to a tube. The can you can use what you need and keep the rest for later, the tube is a one shot deal. PR 1422 B 2 is what I would use. This info may be updated or an alternative may be available.(my can lists 1998 as mfg date).
The Dow Corning stuff that I suggested is a "Fuel Proof Silicone" It has worked for me in to seal fuel tanks flanges, and they can be taken apart if need be.
