Author Topic: engine painting- fin repair and curing w/ heat gun (Read 8980 times)

greasy j · « **on:** April 04, 2010, 11:44:29 PM »

my cylinders and head have busted fins. I have one of them that I could weld on, but there are a few corners busted off. what can I use to repair the busted corners. some type of epoxy? weld the only option? I will paint after so it doesn't have to match.

and after I paint can I use a heat gun to cure instead of the oven? I was thinkin a temp gauge and heat gun might work? crazy?

I see some people paint their engines all put together, I assume this is because they are not doing a rebuild. it is preferable to do in pieces, correct? this was my plan. and how do people cure whole engines. for that matter how do you cure anything in an oven? by hanging from a screw in the top or something? usually when I paint something I figure out how to hang it and let it cure in the spraybooth(which doesn't go to 120) I'm trying to imagine how this will work. my gfriend won't mind me using the oven, she's ultra-supportive of my moto ambitions. but it would have to lay on something which would f up the paint, right?

I have checked the other engine paint posts, they're mostly about prep. I am a preppin pro. just need to figure out this curing thing.

thanks for all your guys' help so far!

faux fiddy · « **Reply #1 on:** April 05, 2010, 12:00:40 AM »

I think people use the weldrod itself to build up a fin, a then grind it to size if it's a small enough chip.

greasy j · « **Reply #2 on:** April 05, 2010, 12:11:12 AM »

Quote from: poor boi on April 05, 2010, 12:00:40 AM

I think people use the weldrod itself to build up a fin, a then grind it to size if it's a small enough chip.

that's what I thought would work. but for such little spots I thought maybe epoxy(jb weld) would be good enough. with the heat, though maybe not. I'll see if I can get my buddy to weld it up then I can grind it down to match the others.

faux fiddy · « **Reply #3 on:** April 05, 2010, 12:35:15 AM »

Ifyou try JB let s know what happens. Ihave acrake finr twotha I would like to be pretty again, but for now it's "adding character." I figure JB will turn loose eventually, but who knows. It works best on broad surfaces. A friend used it all over the intake side of his rz 500 when re-shaping the intake ports, and no problems so far, but that was a thin bit over a larger surface. A large surface held by a thin bit, like a fin might not last as long.

But it will be there for the time being. The guy that welds can probably fix it on the bike if it fails.

Edit: Another thing I used on a cracked trooper head was made just for mainfolds. It was one part, (not epoxy) but was supposedto withstand a cople thousand degrees. It asn't hardly a sticky,more like silver clay and I wasn't able to do a erious mileage check on how it held up in the mileage test, but I drove it for a bit.

greasy j · « **Reply #4 on:** April 05, 2010, 12:51:22 AM »

one trick for fixing things where edges meet is to cut grooves/channels in both pieces on the faces of the piece, not on the edge. then the epoxy filler. like creating shoe laces or stitches to hold it together. when you sand it flush there will be filler left holding the pieces together.

in this case without the piece being attached I would just dig channels in the fin I am attaching to and let the jb weld fill those channels holding the added piece on with more than just the edge. make sense? this works for plastic repair.

wildcatmahone · « **Reply #5 on:** April 05, 2010, 06:39:14 AM »

Yo greasy I'm looking into fixing a couple fins now as well. Jb Weld is outta the question for me as I simply dont trust it as a long term solution. I have a set of alumniweld rods from Eastwood that I was going to use but am now having my doubts. Not sure if the head fins can be brought up to right temperature to use that stuff (as the fins were designed to efficiently dissapate heat ). The only other options without Tig welding I am looking into is Lab Metal or Devcon Aluminum Putty for repair. I was also considering using some 6061 flat bar cut to shape of the missing pieces and then tie it all in and grind to final shape. And yeah, grooving or scarfing the mating surfaces will give you a stronger joint. You can use a heat gun to cure set it to 500f and keep it moving around the part to bake the paint on.
Cheers
Wildcat

greasy j · « **Reply #6 on:** April 05, 2010, 11:10:36 AM »

Quote from: wildcatmahone on April 05, 2010, 06:39:14 AM

Yo greasy I'm looking into fixing a couple fins now as well. Jb Weld is outta the question for me as I simply dont trust it as a long term solution. I have a set of alumniweld rods from Eastwood that I was going to use but am now having my doubts. Not sure if the head fins can be brought up to right temperature to use that stuff (as the fins were designed to efficiently dissapate heat ). The only other options without Tig welding I am looking into is Lab Metal or Devcon Aluminum Putty for repair. I was also considering using some 6061 flat bar cut to shape of the missing pieces and then tie it all in and grind to final shape. And yeah, grooving or scarfing the mating surfaces will give you a stronger joint. You can use a heat gun to cure set it to 500f and keep it moving around the part to bake the paint on.
Cheers
Wildcat

wow. great info. thanks. let me know if you get yours fixed and how you did it. I don't have much welding experience so I don't know what alumiweld entails. but my buddy can do mig and tig welding and has both types of welders in his shop. I plan on taking a class later this year. after my engine overhaul class.

so I can cure my engine paint with a heat gun? I know it's risking bubbling it off, but I don't understand how you hang something in the oven. unless it's a matter of doing one 1/2 at a time and just setting it on the rack. I already used one oven rack in my wash machine blast cabinet I built. can't f up the only one left. hehe.

oven baking paint curing people, how did you do yours?

domer · « **Reply #7 on:** April 05, 2010, 11:29:41 AM »

just from my experience, i wouldnt cure anything inside oven at home! really really f'n stinks. i do some strange smelly #$%* in the kitchen (ever made ganja butter?) and i cant hang with the smell from oven curing paint. the only time i did do it i ended up in my hotel for the night... sleeping on the floor cause my normally tolerant old lady was ready to kill me.
still stunk the next day

greasy j · « **Reply #8 on:** April 05, 2010, 11:38:50 AM »

Quote from: domer on April 05, 2010, 11:29:41 AM

just from my experience, i wouldnt cure anything inside oven at home! really really f'n stinks. i do some strange smelly #$%* in the kitchen (ever made ganja butter?) and i cant hang with the smell from oven curing paint. the only time i did do it i ended up in my hotel for the night... sleeping on the floor cause my normally tolerant old lady was ready to kill me.
still stunk the next day

thanks for the tip. and yeah, we have some special butter in the fridge right now. my gf is an amazing pastry chef and she will make special treats sometimes for me and friends. I had a 'green' cookie last night and conked right out. her carrot cake is freakin amazing! she makes olive oil infused with the stuff as well, which is good with some vinegar and salt to just dip bread in. tasty and numbing!

domer · « **Reply #9 on:** April 05, 2010, 12:49:41 PM »

ha.... my old lady is also a pastry chef. yet i still do the green stuff...

greasy j · « **Reply #10 on:** April 05, 2010, 02:08:55 PM »

hey, you're local. no #$%*. my gf used to work at gary danko, I'm sure your gf has heard of it. place for rich dummys to throw away $.

she's about to open her own chocolate shop. in Jack London Square. I was a skinny guy my whole life, she's tryin to change that.

you have a project goin? I just talked to a guy in Berkeley who does. maybe we could pool resources?

domer · « **Reply #11 on:** April 05, 2010, 02:31:34 PM »

ya im still a skinny guy... so far. she just graduated a yuppie private cooking school here in the city.so she is new to the industry, but still seasoned. i cant stand the #$%* personally. had enough issues with my teeth

always have a project going, 72 500 at the moment... trying to pick up a cb125 (or something like) for the gf, but $$$ is always tight! im always in for pooling resources...

Hannibal Smith · « **Reply #12 on:** April 05, 2010, 05:14:06 PM »

The only true "safe" repair that will not have you wondering down the line, or worse yet, having pieces go AWOL is to have it welded.

My cylinder head is getting Tig welded right now. I had 2 tiny broken fin edges, but that stuff drives me crazy. I considered epoxy, as I am painting my mill too, but in my limited experience, nothing works better to repair fins than expert welding.

gmonkey · « **Reply #13 on:** April 05, 2010, 08:09:03 PM »

Quote from: greasy j on April 05, 2010, 12:51:22 AM

one trick for fixing things where edges meet is to cut grooves/channels in both pieces on the faces of the piece, not on the edge. then the epoxy filler. like creating shoe laces or stitches to hold it together. when you sand it flush there will be filler left holding the pieces together.

in this case without the piece being attached I would just dig channels in the fin I am attaching to and let the jb weld fill those channels holding the added piece on with more than just the edge. make sense? this works for plastic repair.

To extend that method, why not drill holes around where you're attaching the piece to and the piece itself, connect the holes with grooves, tie the piece in place with wire through the holes then cover the wire in the grooves and the holes with jb weld and sand flush? Might have to resort to using a pin-vice with a small drill but likely a good deal stronger than jb weld alone. Could even solder the wire loops instead of just tying them off.

greasy j · « **Reply #14 on:** April 05, 2010, 08:15:47 PM »

Quote from: Hannibal Smith on April 05, 2010, 05:14:06 PM

The only true "safe" repair that will not have you wondering down the line, or worse yet, having pieces go AWOL is to have it welded.

My cylinder head is getting Tig welded right now. I had 2 tiny broken fin edges, but that stuff drives me crazy. I considered epoxy, as I am painting my mill too, but in my limited experience, nothing works better to repair fins than expert welding.

cool thanks. I have to weld a piece on anyways, so that'll be what I do.

Quote from: domer on April 05, 2010, 02:31:34 PM

ya im still a skinny guy... so far. she just graduated a yuppie private cooking school here in the city.so she is new to the industry, but still seasoned. i cant stand the #$%* personally. had enough issues with my teeth
always have a project going, 72 500 at the moment... trying to pick up a cb125 (or something like) for the gf, but $$$ is always tight! im always in for pooling resources...

sendin ya a pm

greasy j · « **Reply #15 on:** April 05, 2010, 08:21:42 PM »

Quote from: gmonkey on April 05, 2010, 08:09:03 PM

Quote from: greasy j on April 05, 2010, 12:51:22 AM
one trick for fixing things where edges meet is to cut grooves/channels in both pieces on the faces of the piece, not on the edge. then the epoxy filler. like creating shoe laces or stitches to hold it together. when you sand it flush there will be filler left holding the pieces together.

in this case without the piece being attached I would just dig channels in the fin I am attaching to and let the jb weld fill those channels holding the added piece on with more than just the edge. make sense? this works for plastic repair.

To extend that method, why not drill holes around where you're attaching the piece to and the piece itself, connect the holes with grooves, tie the piece in place with wire through the holes then cover the wire in the grooves and the holes with jb weld and sand flush? Might have to resort to using a pin-vice with a small drill but likely a good deal stronger than jb weld alone. Could even solder the wire loops instead of just tying them off.

that's pretty ingenious.

sometimes for plastic repair I'll make a flat squigly out of wire and melt it into the plastic to hold 2 pieces together.

I would prob use your method if I didn't have access to a welder buddy.

greasy j · « **Reply #16 on:** April 19, 2010, 01:38:16 PM »

ok, an update.

I was using devcon (superstrong epoxy) in class to fix chips in the mating surface of the cylinder head and teach said we should fix the busted fin that way as well. it takes a few days to cure up, so I left it over the weekend and when I came back I tried to break it off by hand and could not. I put a lot of force on it, enough to know it'll stick. I still need to file and sand it down, then try to bust it off again. if I can't then I'll trust it.

if ya wanna see pics, click on the link at the bottom- 'project ultra'

as far as painting engines and curing I got advice from the teach on that. he has painted tons of engines and has been building bikes and engines and racing for a long time and has tried lots of different things.

he told me he has used the vht, ceramic paint and everything else available and the best longest lasting stuff is the commonly available rustoleum high heat barbeque paint. it comes in black and silver, which is all I need. according to him it is longer lasting than anything else and needs no curing process.

this stuff: http://www.rustoleum.com/CBGProduct.asp?pid=112

wildcatmahone · « **Reply #17 on:** April 19, 2010, 05:01:58 PM »

What type of Devcon putty did you use? The aluminum putty? Let us know how it works out?

-Wildcat

Hondell · « **Reply #18 on:** April 20, 2010, 11:37:29 AM »

I used aluminum based epoxy on my fins (many of them) 5 years ago and still going strong. Zero failure. I tried putty also but was concerned of the "dry" way it adheres.

greasy j · « **Reply #19 on:** April 21, 2010, 01:47:56 PM »

Quote from: wildcatmahone on April 19, 2010, 05:01:58 PM

What type of Devcon putty did you use? The aluminum putty? Let us know how it works out?

-Wildcat

not sure. the stuff is at school. I'll find out on thursday and let you guys know.

greasy j · « **Reply #20 on:** April 28, 2010, 11:39:19 AM »

the devcon said ceramic on the jar. I used it to build a couple fin corners that were broken off last night. as in make a new chunk out of the stuff instead of reataching something. it is blood red w/ a black hardener.

it's hard to keep it from sagging while it dries, but it dries incredibly hard. I tried to fix the busted corners with some high heat epoxy for plumbing and then tried to break them off after curing. it was easy, too easy.

tried the same with the devcon, no way it's coming off without a hammer. and I can't make a dent w/ my fingernail if I push real hard, unlike almost any other filler. it's also rated to 400 degrees. I think it'll work out pretty well.

I would feel safe recommending this stuff to others who don't want to go through the hassle of welding alum.

of course, you will have to paint after as it doesn't match.

wildcatmahone · « **Reply #21 on:** April 28, 2010, 04:27:40 PM »

Hey thx for the update on that repair epoxy, I knew there had to be an alternative to TIG that would be up to the job. Can you please get the product code of the Devcon Ceramic that you used there is actually a couple different ones listed as Devcon Ceramic. Is it maybe this one?
http://www.drillspot.com/products/322456/Devcon_11760_Ceramic_Repair_Epoxy

At 135 bucks a pop I wanna make sure I get the right one!

greasy j · « **Reply #22 on:** April 28, 2010, 06:17:48 PM »

Quote from: wildcatmahone on April 28, 2010, 04:27:40 PM

Hey thx for the update on that repair epoxy, I knew there had to be an alternative to TIG that would be up to the job. Can you please get the product code of the Devcon Ceramic that you used there is actually a couple different ones listed as Devcon Ceramic. Is it maybe this one?
http://www.drillspot.com/products/322456/Devcon_11760_Ceramic_Repair_Epoxy

At 135 bucks a pop I wanna make sure I get the right one!

it was in grey containers w/ red lettering. I can't find it on their website, so they may have changed the label. same size, though and I am pretty sure it was the one you linked, but not certain.

I go back on thursday, I can check then to make sure. and I'll look at my pics to see if I can find one w/ the can in it.

greasy j · « **Reply #23 on:** April 30, 2010, 12:13:00 AM »

so the stuff was missing, I couldn't find it at class tonight. someone put it who knows where.

but it is a pretty old jar, they may have come out with a new formula or just changed the label. it says brushable and ceramic on it and the school has it specifically for engine applications so I am pretty sure it's the one you're linking to, I checked their site and there's nothing else it could be. it even say's it's red, so it must be the stuff. i think...

bucky katt · « **Reply #24 on:** April 30, 2010, 12:30:59 AM »

any painted parts that will fit, get cured on my gas grill. works great

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Author Topic: engine painting- fin repair and curing w/ heat gun (Read 8980 times)