Help - Removing thin deck plugs and stubborn screws

[zak]

I am working on a 60 foot classic boat de and re caulking the teak deck.

The job now is to remove all (over 1000) the 10mm plugs and screws, re counterbore and replace the screws and plugs.

The reason for removing is where the deck has worn, some of the screws are showing, and many of the plugs are wafer thin, potentially allowing leaks. I have a few difficulties that I could do with some advice on to help speed things up given how many I have to do.

1. Removing the shallow (and deep) deck plugs, at the moment I am using a small gouge or round chisel, cutting round inside the plug and eventually flicking out the surplus, then cleaning up with the gouge. I have a 3/8 forstner coming next week so that may help providing I can get dead centre. I thought about a perspex guide with a 3/8 hole in it to offer over the plug, and use the forstner through that. May work, we'll see. Any thoughts, ideas please?. The forstner may run off where the bronze screws are close to the surface.

Is there a plug cutter and counterbore available between 10mm and 12mm, slightly bigger than 10mm would be great but I suspect its not an option?

2. Removing the stuck bronze screws 10g x 2 inches. Under the teak is not ply but an epoxy subdeck (laid in 1992). ALL the screws seem to be stuck at that layer, so its possible the teak was laid on wet epoxy, I'm not sure. Many of the screws are snapping presenting a nightmare of drilling out the remainder. The deck beams are Mahogany. My most successful method so far is using a 60w electric rope cutter with a modified blade to transfer heat into the screw. I'm having to use it well beyond its design spec. I could do with more heat. This has reduced the snap rate but not enough. It was also suggested to hit the screw with a driver and hammer before and after heat but I dont feel that this is helping as the screw heads are sitting on firm teak.

I have a fast car waiting if things dont improve !!!

 

[Talulah]

To remove the teak plugs I use an electric drill with standard drill bit slightly smaller than the plug size. This is so I don't oversize the hole when not placing dead centre. Unscrewing the screw removes any remaining plug bits. For stubborn screws I place pozi screwdriver in screwdriver and hit screwdriver with a hammer. Yours sound much harder and I would suggest trying an electric impact screwdriver.
Once the screw is out clean up the hole with a Fortsner bit, If you don't have a Forstner bit use a standard drill bit with the torque on the lowest setting. If you don't the drill bit will bite and drill straight through the deck before you can get your finger off the trigger.

I make my own plugs using a plug cutter from Screwfix but ready made plugs are available.
The best plugs I've seen were by Robbins Timber in Bristol. These were turned to shape instead of drilled out and so had a definite taper with 5 plugs in a strip. However, they were extremely expensive at about 30p each.

 

[Poignard]

I don't envy you that job!

1. The idea of using a Forstner bit with a guide to remove the old plug seems good to me. According to the old boatbuilding books, plugs should be glued in with varnish so that they can easily and cleanly be jacked out by driving a woodscrew into the centre. This rarely seems to work for me (I suspect the builders used glue) and I nearly always end up excavating bits of broken plug

2. I have had a lot of broken bronze screws to remove from my boat and I have found this type of extractor works very well.

http://www.woodcraft.com/category/2000983/screw-extractors.aspx

They leave a clean uniform hole into which you can glue a piece of dowel.

It's important to remember to turn them anti-clockwise and to use a very slow speed drill. Also you must keep removing the tool and blowing (or vacuuming) the dust out of the groove, otherwise the tool will overheat and lose its temper.

3. Plug cutters and screwsinks are available from many sources (Google 'tapered plug cutter'). Using the ready made tapered plugs recommended by Talulah will save time but they are expensive. If I needed a thousand I would try and negotiate a quantity discount.

 

[ccscott49]

I have just done this job, 2500 plugs and bronze screws. You are right, heat is the only way of breaking the epoxy bond, we used a large heavy duty soldering iron, with custom made (homemade) bit, hold that on the screw and it works a treat, we also used bit and brace, with screwdriver bit, for screw removal, cleaning the groove in the screw first, replacing any damaged screws, mine were 2 1/2" x 10's also. The plugs we used a small sharpened screwdriver and dug out the plugs, leaving any that are deep enough in. they can be done at your leisure later when they show.
Due to slight damage to the holes from plug removal, mine were 1/2" plugs, we went to 15mm plugs, using a 15mm, countersink to deepen the counterbores, it stays in the centre and gives a nice smooth hole for the new plug. My plugs were glued in with cascamite. New ones with varnish

 

[Graham_Wright]

You could try obtaining a steel boss drilled through the centre slightly smaller than the screw core diameter. Locate over the plug and drill through into the screw with an ordinary HSS drill. Then use a tap extractor (very coarse left hand thread) to remover the screw. The remains of the plug should fall out.

Where did you find a mortgage for the rplacement screws?

 

[West Coast]

I have been carrying out a more gradual replacement program of worn deck plugs on the deck of my Starlight - say 15 or so per year.

Removing exposed screws has been straightforward for me. Existing teak plugs were 3/8" (9.5mm). I bought a pack of 10mm dia teak plugs for replacement.
I used a conventional drill (very carefully!) to deepen the hole slightly to allow the screw, when refitted, to sit lower into the teak plank. But, before inserting the screw back I used one of these to create an accurate clean hole for the new plug:

http://www.dk-holdings.co.uk/comp/counbore.html Bought a 10mm version

I appreciate that this tool is designed for harder materials such as FRP, but for a small job like this, it works fine, and most importantly, is totally controllable using a cordless drill. The company make these to order, so made one to my specs. The plain centre spindle guides the tool perfectly centrally in the hole, giving a clean edge finish.

 

[Billjratt]

Is that tool going to be available on the club's "borrow list" Simon?

 

[West Coast]

Is that tool going to be available on the club's "borrow list" Simon?

Good idea, answer has to be yes! When do you want to borrow it?!

 

[zak]

Thanks for all the input, oh boy do I need it !! Looks like I'll carry on with heating the screws to break the epoxy bond, wish I could get a bit more heat in them, On Monday I think I may put a tube heater below each beam before I start removing the screws, so they are at least off of cold before I apply the hot knife blade.

Re the plugs, the customer is not keen on going from 10 to 12mm and I have to agree with him, it would look a bit big. Shame there isn't anything in between.

the fast getaway car is warmed up and ready to go !!

 

[BlueLancer]

I would inclined to use a Brace and Bit for removing the screws. You will be surprised how much pressure you can apply to the screw.and has worked for me against screws set in 1969. Electric drills/screwdriver unless on a very slow speed will be subject to climb out which could damage your deck, also they do not have enough torque.

 

[pvb]

I would inclined to use a Brace and Bit for removing the screws. You will be surprised how much pressure you can apply to the screw.and has worked for me against screws set in 1969. Electric drills/screwdriver unless on a very slow speed will be subject to climb out which could damage your deck, also they do not have enough torque.

As the OP said "Many of the screws are snapping...", it seems he doesn't have any problem in applying torque!