unbolting a plate bedded with 5200

[George Dewey]

I need to remove this square plate, ideally without cutting up the deck. Those bolts have a 3/4 inch slot and I can't find a screwdriver anywhere near that big. We got the nuts off easily but the bolts wouldn't budge. CCF made the boat, I emailed them and they said it's bedded with either 4200 or 5200. I know about Debond, but I don't think I can get it under the plate (on the top side), and I think the bigger problem is getting the bolts out. I'll try a heat gun, but any other ideas? I think once the bolts are out the rest won't be too bad.

Any idea where such a big screwdriver can be found? I checked local Tru Value stores, Home Depot and Lowes, and Amazon and Ebay. No luck.

 

[harrygee]

If you have room underneath, put the nuts back on flush with the end of the bolts and give them a whack with a hammer.

Otherwise, if you don't mind mangling the slots, an impact screwdriver with a blade of about 1/2" will do the job.

Or get hold of some big steel washers and hold one in the slot and lever it with a big shifter / wrench.

More than one way to balls up a job.

Cheers

 

[Zonker]

I had big flat bolts like that - the PO used epoxy to hold the chainplates in.

I used a 1/2" impact gun with impact bits. And a small pinpoint butane torch to locally soften the epoxy on the bolts.

You want something that looks like this.  Get thee to a proper tool store not a big box.

https://www.amazon.ca/Stanley-J5444A-2-Inch-Socket-4-Inch/dp/B00209S3OO/ref=pd_lpo_1?pd_rd_i=B00209S3OO&psc=1

 

[Son of Hans]

I'm guessing when you do all that and get the bolts (machine screws, actually) out, the plate still won't move.  A multi-tool with a scraper blade is probably your next purchase.

 

[kiwin]

In addition you can probably get a blade under the plate to cut tye sealer out. Use a cheap flush cut saw and protect the deck with tape.

 

[Mid]

get a blade under the plate

this

 

[yoyo]

What Zonk said for the bolts.  Impact rated large straight slot and impact driver.

 

[IStream]

I'd try to hammer/press those bolts out first. A small bottle jack with some makeshift support underneath would do the job cleanly in short order. 

 

[George Dewey]

I had big flat bolts like that - the PO used epoxy to hold the chainplates in.

I used a 1/2" impact gun with impact bits. And a small pinpoint butane torch to locally soften the epoxy on the bolts.

You want something that looks like this.  Get thee to a proper tool store not a big box.

https://www.amazon.ca/Stanley-J5444A-2-Inch-Socket-4-Inch/dp/B00209S3OO/ref=pd_lpo_1?pd_rd_i=B00209S3OO&psc=1

View attachment 472200

Thanks for so many great replies so quickly! I just ordered this, it was available with a 3/4 inch wide bit. I also ordered a 24 inch breaker bar to go with it. The idea of wacking my deck with an impact driver or a hammer from underneath makes me pretty nervous. Since you guys say it's okay to do I'm not against it, but I'm hoping the breaker bar and bit with some heat get the job done. I really don't want to pound my deck, from above or below. But there is plenty of room below, it's in the anchor locker. 

Would a heat gun be sufficient, or do I need to get a small torch? 

In addition you can probably get a blade under the plate to cut tye sealer out. Use a cheap flush cut saw and protect the deck with tape.

Yeah I think once the bolts are out, I can use a thin blade forced between the plate and deck to cut the 5200, then clean it all up with Debond. I'm sure that's easier said than done. 

Use the old school approach, a brace and bit. Flate blade bits are available, often at 2nd-hand stores. I routinely use a b&b to loosen big screws (and also carefully tighten them.)  More easily controlled (by me) than power tools. Heat helps too.

What's a B&B ??

 

[George Dewey]

Oh wait, I just Googled M18 impact driver. This is a power tool, I thought you guys meant the handheld one you hit with a hammer. Did you mean one of these power tools use for driving bolts into cement? 

 

[slug zitski]

I need to remove this square plate, ideally without cutting up the deck. Those bolts have a 3/4 inch slot and I can't find a screwdriver anywhere near that big. We got the nuts off easily but the bolts wouldn't budge. CCF made the boat, I emailed them and they said it's bedded with either 4200 or 5200. I know about Debond, but I don't think I can get it under the plate (on the top side), and I think the bigger problem is getting the bolts out. I'll try a heat gun, but any other ideas? I think once the bolts are out the rest won't be too bad.

Any idea where such a big screwdriver can be found? I checked local Tru Value stores, Home Depot and Lowes, and Amazon and Ebay. No luck.

View attachment 472180

View attachment 472181

To remove sika bedded hardware I use a stiff blade, strike putty knife and tapered hardwood wedges 

start at a corner , drive the putty knife under the plate perhaps 1/2 inch then  take a hardwood wedge and position it between the putty knife blade and the fiberglass substrate then drive the wedge in with a hammer 

the force  breaks the bond and lifts the plate

you may need to work around the plate with the wedge, putty knife 

 

[slug zitski]

In future if  you contaminate the hardware surface with shoe polish , spray lube or a nylon sheet gasket  … you will avoid the adhesive bond 

 

[slug zitski]

 

[Quickstep192]

I use a creme brûlée torch in these situations. It's a much more focused flame. I also use the creme brûlée torch for burning the ends of rope. Remember, fiberglass is highly flammable. 
 

Also, the impact from an impact driver is it the direction of rotation, it's not beating on the screw. An impact drill is beating on whatever you're drilling into. 
 

To turn the screws, you might try doubling up nuts and tightening them together and seeing if you can turn them with a wrench. 
 

I've heard of people using guitar strings to sever the 5200. Wrap each of the ends of the string around a dowel and work it under the plate. 

 

[yoyo]

Oh wait, I just Googled M18 impact driver. This is a power tool, I thought you guys meant the handheld one you hit with a hammer. Did you mean one of these power tools use for driving bolts into cement? 

Yup - power tool.  Doesn't have to be Milwaukee that's just the brand I own.  This is the kit I got years ago.  Came as a combo with the drill.  Milwaukee M18 18-Volt Lithium-Ion Cordless Drill Driver/Impact Driver Combo Kit w/ Two 1.5Ah Batteries, Charger Tool Bag (2-Tool)-2691-22 - The Home Depot

They also make 1/4" drive adapters for different socket sizes.  You will need one that fits whatever drive you get.    

Milwaukee SHOCKWAVE Impact Duty 1/4 in. Hex Shank Socket Adapter Set (3-Piece)-48-32-5033 - The Home Depot

After bolts are removed put some halyard tension on the fitting.   Put tape around the fitting to prevent marring the deck.   And then work a putty blade under it (like the one Slug suggested) with a hammer.   Wedges are good and more halyard tension.

 

[George Dewey]

I use a creme brûlée torch in these situations. It's a much more focused flame. I also use the creme brûlée torch for burning the ends of rope. Remember, fiberglass is highly flammable. 
 

Also, the impact from an impact driver is it the direction of rotation, it's not beating on the screw. An impact drill is beating on whatever you're drilling into. 
 

To turn the screws, you might try doubling up nuts and tightening them together and seeing if you can turn them with a wrench. 
 

I've heard of people using guitar strings to sever the 5200. Wrap each of the ends of the string around a dowel and work it under the plate. 

Yeah I'm aware of the fire hazard, which is why I'm not excited about the torch. I do have a heat gun. I'll try that first, hopefully it's hot enough. I like your creme brulee torch idea. 

Once I have heated the heck out of these screws and mashed them with an impact driver, will I need to put new ones back in or can I reuse the existing ones (assuming I don't muck up the slots)? 

 

[slug zitski]

Heat can work but ……..

Sika is soft , you can remove fasteners without a fuss 

for fasteners set into epoxy heat is used 

an industrial strength electric soldering iron with the suitable screw driver bit on its tip 

heat the screw ,,, use a normal screwdriver to extract ,,, not the soldering iron 

 

[GMiller]

I have really screwed this up before, hammering from below when it gave.  Went topside to revel in my accomplishment when I realized I had torn off the top skin and the gelcoat...  I hate 5200. 

 

[yoyo]

Do not use old bolts - buy new bolts.   316 SS, passivated, flat head socket drives