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  1. #1
    Petty Officer 2nd Class jburn25's Avatar
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    Default Removing fiberglass (grinding?)

    I've got about fifteen projects going on at one time in my boat, but my main goal is to make the boat very sturdy and capable to handle chop without rattling apart. So I ordered some AV rivnuts (wellnuts) to attach the deck to the bottom of the boat with. Yesterday I took the deck out of the boat and was exposed to a horrendous site the PO didn't tell me about. The bottom of the boat has tons of fiberglassing around all the welds on the ribs and all the way around the center console. Evidently some ribs broke and instead of just welding them, he welded them and then fiberglassed over them. Well, he did a poor welding job on the ribs and the console and I want to have it all professionally welded but I have to get all the fiberglass pulled up first. Some of it just pulled up in big sections, the rest I tried to grind off with my angle grinder, but I'm not sure that's the best method.

    Anyone have any experience with this?

    Also, should welding an aluminum center console to the ribs in the bottom of my boat be sufficient to hold it down?

  2. #2
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    Default Re: Removing fiberglass (grinding?)

    Before you start grinding away try and use a stiff scraper blade and see what it will remove. Just get a good grip on the bottom of it all and go from there.
    Sanding or grinding on an aluminum hull will produce heat, and it will warp if not awfully careful.
    If there are big chunks coming off now then the chances of the rest being able to be ripped off ( excuse the pun ) are pretty good.
    The left over residue should be tackled with a random orbital sander with something like 80# paper. Again, be really careful with any sanding or grinding on that hull. It can turn to butter really fast.
    There aren't any chemicals that will remove dried gel or epoxy - so you're pretty much stuck with the abrasive way. Easy does it !!!
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  3. #3
    Moderator Bob_VT's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Knotted wire cup brush and a 4 -1/2 in grinder for power will eat that fiberglass away..... it will even eat the aluminum if you are not careful.

    I would suggest mounting the console to a seperate sheet of aluminum and mount that to cross bracing in the boat. That will distibute the laod and force on the console.

    You might as well get a can of gluvit to really seal the new rivets and welds properly too.

    Moving this to Restoration Section....... got any pictures?
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  4. #4
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    Default Re: Removing fiberglass (grinding?)

    As you can see, there are many that don't know how to prep for fiberglass. There is a prybar that is used for interior trim woodworking, "lowes,home depot", it is thin and may help pry more loose.

  5. #5
    Moderator Bob_VT's Avatar
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    Default Re: Removing fiberglass (grinding?)

    The thing I did not mention is to wear safety equipment..... goggles, mask and long sleeves. That fiberglass dust is nasty stuff...... if you have any young children.... keep them away.
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  6. #6
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Ok, sounds like great advice so far. I've got a 4.5 inch angle grinder and I have one of those tough wire brush attachments so I'll try and use that. I had been using one with the regular grinder blade but I think it was a bit much. I'm really bad about taking pictures and uploading them, but I will definitely try.

    I got a really good deal on the boat, but it seems like its kind of catching up with me having to do some of this work. It's a welded boat and I noticed several of the ribs had cracked in the middle of the boat. The PO had taken angle aluminum and run it along both sides of the ribs and then run bolts through them to sturdy up the ribs. Then he laid fiberglass over it. I'll probably leave all that fiberglass because I think its structurally ok. My main concern is getting the fiberglass off the console base because I REALLy need it to be solid and I think welding is the way to go. I'll try and find a sheet of aluminum to attach it to first.

  7. #7

    Default Re: Removing fiberglass (grinding?)

    Hey have the welder remove the glass needing to be removed. If they weld they know how to glass. Also he may need to remove more than you did as fiberglass can catch on fire while welding.

  8. #8
    Honorary Moderator Emeritus tashasdaddy's Avatar
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  9. #9
    Moderator Bob_VT's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Quote Originally Posted by jburn25 View Post
    ........My main concern is getting the fiberglass off the console base because I REALLy need it to be solid and I think welding is the way to go. I'll try and find a sheet of aluminum to attach it to first.
    Welding is good.... here is a hint..... visit a construction company or a road maintenence company and see if you can scrounge al old road sign ..... even an old stop sign..... they are anodized aluminum. Just don't steal one
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  10. #10
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Dang, TD, I know you're right about the safety equipment stuff, just don't want to pay 60 bones for a respirator. I'll have to see what I can come up with regarding a street sign, don't need any trouble with the po-po right now in school so I definitely won't be stealing one lol. The welder I talked to didn't want to do any removing of the fiberglass. I guess he's busy. speaking of which...is 100 dollars an hour really high for aluminum welding? He's going to have to grind off all the old welds around the ribs and everything first so he quoted me for 30 hours to weld six cracked ribs. We haven't talked price for the console yet.

  11. #11
    Supreme Mariner oops!'s Avatar
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    Default Re: Removing fiberglass (grinding?)

    [QUOTE=jburn25;1955165]Dang, TD, I know you're right about the safety equipment stuff, just don't want to pay 60 bones for a respirator. QUOTE]

    hi.....you can get resporators a little cheaper.....but !

    (sorry to be blunt).....if you cant afford to get a resporator...you cant afford to fix your boat.....

    those little dust masks wont work...at all...i dont care how careful you are...fiberglass dust NEVER EVER BREAKS DOWN IN YOUR LUNGS....EVER....it is there for life......

    all of us that have done glass grinding before.....know....within 1 hr of grinding....you are standing in an inch of fine fine powder.....and the room looks like a clowd......really...there is that much dust.....

    get a real resporator.......or cough up a lung....your choice !


    ......p.s.......i dont mean this post to sound harsh.....but what good is a boat if your dead from lung desease?
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  12. #12
    Moderator Bob_VT's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Quote Originally Posted by jburn25 View Post
    Dang, TD, I know you're right about the safety equipment stuff, just don't want to pay 60 bones for a respirator. I'll have to see what I can come up with regarding a street sign, don't need any trouble with the po-po right now in school so I definitely won't be stealing one lol. The welder I talked to didn't want to do any removing of the fiberglass. I guess he's busy. speaking of which...is 100 dollars an hour really high for aluminum welding? He's going to have to grind off all the old welds around the ribs and everything first so he quoted me for 30 hours to weld six cracked ribs. We haven't talked price for the console yet.
    $3000 in welding charges OMG!

    Okay post pictures and stay away from that welder.
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  13. #13
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    whoops! I mis-typed that part about how many hours he quoted me for. He quoted me for 3 hours, not 30 haha. So he said 300 bucks total to grind and weld six cracked ribs.

    oops: Thanks for the response. I think you're totally correct. In fact, I have already made plans to go buy a respirator today. Didn't mean to make it sound like I wasn't going to, just that I was reluctant to add to the expenses of repair lol.

    Found some at harbour freight for around 30 bones, think they'll do?

  14. #14
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Here's some pictures of the fiberglass on the ribs of the boat and around the bottom of the console. On the rib in front of the console you may be able to see the pieces of angle aluminum that are running along each side.
    995D55B8E4924ADE.jpg

    C597B668597C4D73.jpg

    FBD0267DEFE34BB6.jpg

  15. #15
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    ok, those were a tad bit too small to use for anything so here's some enlarged versions.
    IMG_5481.jpg

    IMG_5482.jpg

    IMG_5483.jpg

    You can see in the bottom of one of the pictures where the welds have cracked where the ribs meet at the bottom and side of the boat.

  16. #16
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    Default Re: Removing fiberglass (grinding?)

    Look around in your neck of the woods and see if you can't find a technical school or trade school that has welding classes. Haul it off to them and your price will come down a lot. Possibly even free - you supply parts and material.
    The students will all have a qualified instructor looking over their shoulder.
    Ah, just a thought.
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  17. #17
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Ok, well after calling a few local shops I found a couple guys with lower prices (65$ per hour). I'm going to bring the boat by there place in the morning and see what they think they can do.

    I got all the fiberglass off of the appropriate areas today using the grinder and wire brush attachment. Sure am glad I don't have to do that crap everyday. The respirator was a huge help. That white powder got everywhere and looked like Christmas.

    Basically, what the PO did was try to fix several cracks across several of the ribs by putting angle aluminum along each side of the rib and then fiberglassing the heck out of the cracks. I think the cracks were caused by the weak/broken welds on the corners at the side and bottom of the boat allowing the gunnels to move a little bit. If those welds were properly made I don't think the ribs would have any problem.

  18. #18
    Captain erikgreen's Avatar
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    Default Re: Removing fiberglass (grinding?)

    $100 an hour isn't too bad for someone welding aluminum. It takes some skill to do it, plus a welding rig set up for aluminum. Plus there's a lot of labor involved in grinding and pre-cleaning the metal in place. You have to make sure the metal to be welded is as clean of impurities as possible, down to the microscopic level, it's not enough to just grind it shiny like with steel.

    Note that if you use any anodized metal in your boat (like a street sign) you'll want to know what materials were used for anodizing... probably they'll have to be removed with acid or ground off before they can be welded. If you're not going to weld them, then you're in great shape because the anodizing will protect the metal.

    Erik
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  19. #19
    Captain erikgreen's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Quote Originally Posted by jburn25 View Post
    Basically, what the PO did was try to fix several cracks across several of the ribs by putting angle aluminum along each side of the rib and then fiberglassing the heck out of the cracks. I think the cracks were caused by the weak/broken welds on the corners at the side and bottom of the boat allowing the gunnels to move a little bit. If those welds were properly made I don't think the ribs would have any problem.
    Looking at those pics, from what I can see I'd guess it wasn't a problem with the original welding or assembly. It looks like the sides of the boat have been subjected to much more force than originally designed, possibly due to an extra large engine, high speed runs in big waves, someone sitting on them over time, etc.

    I don't think just welding them is going to last all that long... if it were mine I'd weld a separate piece of aluminum on each side of the joint, like a knee, to transfer force from the bottom "rib" to the side "rib".

    The new welds you're going to put there will be strong, but inflexible, so I'm thinking the new joint will fail on either side of the new weld after some use.

    With the interior structure of that boat, definitely consider a plate to mount the console on, or maybe even consider a fiberglass console, which would flex more than aluminum and tend to crack less.

    Why exactly do you need the boat/console to be super strong?

    Erik
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  20. #20
    Moderator Bob_VT's Avatar
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    Default Re: Removing fiberglass (grinding?)

    A few pieces of bracing and a good size sheet of aluminum to spread out the load. I see that fuel line which means you have the tank under the console? Well a 6 gallon tank equals about 45 lbs.... the console and you all in line and it creates alot of load.

    I would add some bracing and beef up the current aluminum.

    Very nice looking boat.
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  21. #21
    Petty Officer 2nd Class jburn25's Avatar
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    Default Re: Removing fiberglass (grinding?)

    Thanks for the replies.

    Erik Green, I think you are dead on. I think the sides have been subjected to more force than was originally designed for this 20 year old boat. I believe the PO decided to weld them himself when they became weak and didn't do such a hot job. I actually e-mailed him and he said there aren't any good aluminum welders in his area so he tried it himself and also the fiberglass. A good weld across those joints should be strong, but like you say it probably won't last that long with no give or translation.

    The problem with the original design that I can see is that the ribs aren't one piece by any stretch of the imagination. I'm not sure what common procedure is on these ribs, but in this boat its basically a rib on the bottom which meets up with a rib on each side. So theres only one place where the ribs meet on the "top" of the joint which only allows for a very small welding area. I think adding some sort of traingle piece of aluminum on each side of each joint like Erik is saying should in fact provide some stability. I might go to the local aluminum junkyard and get some sheets of aluminum and pre-cut them with the grinder and just get the welder to weld them for me.

    I need the console to be sturdy because this boat is a true flat bottom AND center console. Most flat bottoms aren't center consoles and most center console boats are mod-V at least. I take this boat out in places like Venice and other inshore areas in south LA where the water gets rough and since I have to stand to drive (as do the passengers) we all hold on to the console for stability. Standing while driving a center console true flat bottom is tough because things get really bumpy. After my last trip, every screw in my floor rattled completely out, my gas tank came unmounted from the deck, and the bolts holding my windshield down sheered off. I don't drive crazy or anything either, just rough misssissippi river.

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