Rookie question I have to ask

[theoldwizard1]

I stole this picture from Waterman's thread.

That is JB Weld plugging up all those holes. I ASSUME the plug of JB on the back side is significantly larger.

1. Does this type of plug/patch actually hold long term and what type of prep is required on the backside ? I guess I'm thinking that any flexing would cause the epoxy to fail. Other threads have used backing plate, but there are just too many holes to do that here. Is this type of repair adequate near/below the water line ?
2. I know you guys use Marine Tex to fill corrosion. Why not here ?
3. Is the recommend procedure for larger non-structural holes at or below the waterline to attach a backer with 5200 and, after it cures, fill the hole with JB/MT ?

 

[dozerII]

Re: Rookie question I have to ask

I stole this picture from Waterman's thread.

That is JB Weld plugging up all those holes. I ASSUME the plug of JB on the back side is significantly larger.

1. Does this type of plug/patch actually hold long term and what type of prep is required on the backside ? I guess I'm thinking that any flexing would cause the epoxy to fail. Other threads have used backing plate, but there are just too many holes to do that here. Is this type of repair adequate near/below the water line ?
2. I know you guys use Marine Tex to fill corrosion. Why not here ?
3. Is the recommend procedure for larger non-structural holes at or below the waterline to attach a backer with 5200 and, after it cures, fill the hole with JB/MT ?

Hey TOW, JB weld just works real well for the job, if you look in my Holiday thread here starting in post 308 http://forums.iboats.com/starcraft-boats/1976-holiday-18-mercruiser-120-a-619470-13.html I give a good description on how I fill the holes, and have never had an issue with them.

BTW a 21 Holiday would be the perfect boat for you

 

[theoldwizard1]

Re: Rookie question I have to ask

Hey TOW, JB weld just works real well for the job, if you look in my Holiday thread here starting in post 308 http://forums.iboats.com/starcraft-boats/1976-holiday-18-mercruiser-120-a-619470-13.html I give a good description on how I fill the holes, and have never had an issue with them.

I read most of your thread but I must have missed

and where there was just screw holes just force JB into the holes then a fairly thick patch of it to act as the backer

• Am I correct that this backer is just a thick layer of JB ?
• Do you tape the top side and put your "glob" on the back while the panel is upside down (so gravity is work for you) ?
• So you feel that sanding the back side with 36/40 grit (and I assume cleaning with acetone) gives enough "tooth" for the JB to hold on to, even with some flex in the aluminum ?
• Why JB and not MT ?
• Why do folks doing riveted patches use 5200 instead of JB or MT ?

I'm good at asking a lot of questions !

 

[dozerII]

Re: Rookie question I have to ask

I read most of your thread but I must have missed

• Am I correct that this backer is just a thick layer of JB ?
• Do you tape the top side and put your "glob" on the back while the panel is upside down (so gravity is work for you) ?
• So you feel that sanding the back side with 36/40 grit (and I assume cleaning with acetone) gives enough "tooth" for the JB to hold on to, even with some flex in the aluminum ?
• Why JB and not MT ?
• Why do folks doing riveted patches use 5200 instead of JB or MT ?

I'm good at asking a lot of questions !

Questions are good. I use JB cuz it is what I can get locally and it is what I have always used (creature of habit) After sanding with 36 I just blow the dust of and apply the JB, and as you said gravity holds it in. I think if a person added a slight bevel to the top side of the hole like Bluefin16 does for his rivets you would stop all possibilities of the patch dropping out.

 

[barato2]

Re: Rookie question I have to ask

there's also the approach of cutting a small patch for under each hole and holding it in place from below while the JB hardens with a "go-bar" arrangement using a flexed wood dowel

 

[classiccat]

Re: Rookie question I have to ask

Hi Wiz...Its funny because I literally just finished my port-side gunwale cap.

1. I beveled both sides of the holes using a large drill bit.
2. cut a bunch of aluminum flashing backers
3. sanded all surfaces touching JB with course emery cloth.
4. wiped all of the surfaces down with acetone
5. placed the backers on individual pieces of frog-tape
6. put a dollop of JB on the backer and stick it to the underside of the hole
7. allow it to settle for a bit, then I come back and flare the JB using a piece of flashing (like a puddy knife)...WARNING: If you do this step too early and the flashing drops-a-bit, you'll get a dimple in the hole.
8. Come back in 2-3 days and hit it with a gator disk...WARNING: Lots of dust!

This is a no-go below the waterline; Use external patches back-buttered with 5200 Riveted in place using solid rivets. :thumb:

 

[theoldwizard1]

Re: Rookie question I have to ask

Hi Wiz...Its funny because I literally just finished my port-side gunwale cap.

1. I beveled both sides of the holes using a large drill bit.
2. cut a bunch of aluminum flashing backers
3. sanded all surfaces touching JB with course emery cloth.
4. wiped all of the surfaces down with acetone
5. placed the backers on individual pieces of frog-tape
6. put a dollop of JB on the backer and stick it to the underside of the hole
7. allow it to settle for a bit, then I come back and flare the JB using a piece of flashing (like a puddy knife)...WARNING: If you do this step too early and the flashing drops-a-bit, you'll get a dimple in the hole.
8. Come back in 2-3 days and hit it with a gator disk...WARNING: Lots of dust!

Thanks for the details ! That would be a lot of backers on Waterman's gunwale cap. Luckily many of the holes are close together and I'm sure you can use one to cover many.

For a 1/2" hole would you backer be about 1" or larger ? (I noticed on moderately sized hole above the water line someone used a heavier gauge backer and a hole filler piece.)

 

[classiccat]

Re: Rookie question I have to ask

Thanks for the details ! That would be a lot of backers on Waterman's gunwale cap. Luckily many of the holes are close together and I'm sure you can use one to cover many.

For a 1/2" hole would you backer be about 1" or larger ? (I noticed on moderately sized hole above the water line someone used a heavier gauge backer and a hole filler piece.)

that sounds about right...you're just giving it something to anchor to.

For large holes, Glen fabricated inserts...these will conserve JB-weld.

 

[heycookieman]

Re: Rookie question I have to ask

Use external patches back-buttered with 5200 Riveted in place using solid rivets. Is this what you would do below the waterline? I have 1 on my transom below the waterline and 1 on the side at the waterline. Thanks

 

[jbcurt00]

Re: Rookie question I have to ask

Is this what you would do below the waterline?...............

HCM: start a thread on your project & the tin-sanity crowd will be all over any questions you have about your project.

But yes, bucked rivets in a patch w/ 5200 for holes larger then a simple fill w/ a rivet hole

 

[heycookieman]

Re: Rookie question I have to ask

Ok will do and thanks.