Fiberglass or Bondo over aluminum??

[SHickey]

Well I usually wait until the fall to pick up a cheap boat to restore but this Mirrocraft 21' F4621 just caught my eye and you know when the trailer is worth more than the boat, you will be in for a real challenging project.

I can only find bits and pieces about this boat and I was hoping someone may have owned one in the past or currently owns one now. It was built in 1976 and it has an aluminum hull, 140 Mercruiser Iron Duke and a MC 1 outdrive. It has a cuddy cabin configuration similar to as Starcraft Chieftian (which is a boat I have always wanted to restore)

The boat has a fiberglass or bondo type of covering from the waterline to the gunnel to simulate planks I guess. The previous owner smacked the front starboard side into the dock and put a bunch of large cracks into the covering. I was wondering if the large cracks and the missing chunks are worth fixing or if I should attempt to remove the covering off of the aluminum hull completely? There are a few other places where this covering is cracked or missing pieces.

I plan on replacing the floors, side deck panels, pedestal seats, motor cover, and the cabin cushion covers and tear out the earth tone brown carpet and white shag "fur" in the cabin ceiling. I would take pictures but I would probably be excommunicated from these forums if you saw the interior and exterior condition of this craft.

If anyone can help me decide how to repair the hull covering damage or if someone has experience with removing this covering from the hull, I would really appreciate your feedback.

Take care

 

[Woodonglass]

You for sure, MUST post pics of this boat. I've never heard of nor seen an aluminum hull encapsulated in fiberglass. I just gotta see this!!!:jaw::clap2:

 

[SHickey]

I am very sorry Woodonglass but even one of my pics seems to be to large for the attachment. Are there any other ways I can get pictures up on to the forum or to you individually? You seem to know alot about hull repair and fiberglass technology. This project repair situation would be right up your alley.

 

[ahmincha]

Try a free photobucket account then then hoover your cursor over img left click mouse will copy image bring it over to this area and paste

 

[SHickey]

Thank you MCPO for the advice. I set up a photobucket account and lets hope these pics download

 

[UConnMRB]

Wow, that is very interesting...is this a custom build? Looks like a fiberglass cap on a tin boat....sorry I am not much help with your questions...I just find this interesting. Hope you dont mind if I tag along. I can see rivets going from hull to gunnel near the transom. Are those fake rivets in fiberglass to simulate metal, or does fiberglass stop and blend at some point from bow to stern?

 

[MTboatguy]

I have owned a few Mirrocrafts over the years and have never seen anything like that, have you emailed them with the serial number to see what they have to say about it?

 

[Woodonglass]

Well cut my legs off and call me shorty!!!:facepalm:

I've never seen or heard of anything like this. EVER!!!! That's Nuckin Futs!!!:crazy: Appears to be about 1/4" thick. Can you bust off a chunk and get a close up of the edge of it so we can see possibly what' it's comprised of? Also, smash a piece with a hammer and see what happens. I would think it would have to an Epoxy Based product in order for it to adhere properly. And how they got the faux planking in there is beyond me. :noidea: I don't have a clue as to how to go about repairing this. WOW!!!

 

[SHickey]

Awesome !! Gentlemen just what I want to hear

What little I know about repair, the rust/grey color of the material reminds me of Bondo (used on cars and such) I am beginning to wonder of the hull was damaged and this material was used to cover up the dents/dings. But it seems to be an extensive fix considering the time and money spent on this material and the ability to make it look like planking.

This is most definitely an aluminum hull so now I have to decide whether or not to knock it all off and see what it is hiding or try to repair the damage with a similar material and go from there??

Thank you all for your responses and maybe some more people can see this and add more information to the mix

 

[gm280]

Unless there would be some type fiberglass clothe in the repair, I don't see it working long without cracking again. But that is just my thinking out loud too...

 

[Scott Danforth]

looks like someone who was a weekend shadetree body mechanic (schlep with a can of bondo) did some repairs, and instead of doing proper metal work, simply bondod over it. However it doesnt look like they did any self etching primer.

Every mirro craft that I have come across has been baked enamel on aluminum. The layer of bondo is a repair (evidenced by the weld pucker marks in your photo)

in the boat building industry, all yachts are faired prior to paint to hide the sins of the builder (Fairing and paint make it what it aint...). however the fairing will not stick to bare aluminum very well without a layer of self etching primer. Bondo and other autobody filler has talc as the thickener. without the first layer of primer, any pin hole or bit of lint will wick moisture to the aluminum, start a bit of corrosion and the fairing (mud, etc.) will fall off.

my recommendation is to strip down the hull, buff the aluminum with appropriate 3m scotchbright cleaning pads, prime with a self etching primer. Then if you need to fair the hull to fix imperfections, look at a true microbaloon fairing compound.

 

[SHickey]

Thank you Admiral for your insight. I also believe I should knock the bondo off and see what the hull is really like. Unfortunately, I don't have any experience fixing aluminum holes, dents or dings and sadly, the port side of the boat looks great!! I would have thought it was sculptured at the factory the way it was done.
I dread the thought of pulling out a mallet and chisel and knocking that crap all off and my hope would be that it will not be permanently affixed to the aluminum.

After I remove the hull covering it will probably lighten the boat by @ 100 lbs, but what disaster will I uncover when the coating is removed

Well, I told my wife this would be a 2 year renovation so what's a couple of extra months to get the hull back into it's original condition. And considering I was going to paint the hull anyway, at least I will be painting similar surfaces.

And UConn MRB, the very top of the cabin was added on some time ago. This boat I believe had an open cockpit but the previous owner rigged up the top and fabricated a doorway to enclose the cockpit for stormy weather fishing. and believe you me it was a real "custom" job

 

[64osby]

Looks like there may be ribs in that hull, that is a good thing.

A few MC's were built with pour in foam and a sealed floor. Hope yours is not one of those.

My current project has some bondo covering the rivets where the side meets the bottom. I heat it with a torch, but not too much, after it peels right off with a painters knife.

Will be watching to see where this goes.

 

[SHickey]

I take it Admiral that you are in the process of removing the bondo from your current project. The picture of your Lone Star Medallion seems to have the same kind of planking design as my Mirrocraft. Does the Lone Star have an aluminum or fiberglass hull? What is covering the 1966 aluminum if it is covered??

 

[64osby]

The LS is Lapstruck aluminum. That is what you are calling planking.

The bondo on it is covering the side to bottom seam, Not the whole side of the hull.

The hull does also have a very poor latex paint job that will be coming off soon.

 

[SHickey]

That is very interesting, I never hear of lapstruck aluminum. Is it a process where a sheet or strip of aluminum is pressed or shaped to give it that look?
BTY, your 21 Mariner reminds me of the 16' Supper Sport I redid @ 5 years ago and that boat turned out very well considering it was a complete gut job right to the ribs and stringers

When you say the "bondo on it is covering the side to bottom seal, Not the whole side" , I am not quite sure what you mean by that? Is the bondo at, below or above the water line?

Sorry to ask so many questions, I just want someone to tell me to leave the sides alone and just fix the cracks, but alas, no one seems to be stepping up Which can only mean I have one hella of job to do and it may get VERY ugly before I am finished.

 

[64osby]

You can see where the bondo was on my Lone Star. Just covered the rivets.

There reason no one is telling you to fix the bondo is because it doesn't belong there and should be removed. I would venture to guess that there will some form of damage to the hull that the PO covered up. My thoughts are someone blasted a few holes in the hull with bird shot of possibly many slugs based on what I see from one of your pics.

Remove it and see what you have, you have nothing to loose.

 

[muskyfins]

This could get interesting.......op2:

 

[SHickey]

Birdshot and deer slugs now that will make a great refurbish story. The consensus is in and I will need to do what I must. I will probably start chipping it away in a week or two. This project is just starting to get interesting. I can post pictures of the stripped hull when it is uncovered.

Thank you all very much for your responses and advice!! This is how I stay out of trouble at home and work

 

[Scott Danforth]

Use a heat gun and a metal putty knife and it should take about 3 hours to remove the pealing bondo