Repairing an archtop guitar bridge-If possible

This refers to the bridge base- the wooden piece on the bottom that sits on the surface of the guitar body. The holes for the bridge posts have been gouged out and the bridge posts are able to move slightly. This causes tuning problems and bad intonation. Can I fill in the holes with some sort of epoxy resin or some such thing ? Something that will make it solid and as good as new? Is this even possible, or should I just chuck it and buy a new bridge entirely?

The bridge base is very important for tone and sustain. I'd be afraid that filler or epoxy would be a rubbery barrier where you're supposed to have a solid connection for coupling. A new bridge base shouldn't be too difficult if you wanted to re-use the original saddle and threaded posts, but be careful since they do vary in dimensions (the spacing and threading of the posts especially). You'd also have to contour the underside of the new bridge base to sit snug against your archtop (whether or not you replace the entire bridge).

Does your guitar have a wooden saddle sitting on thumbwheels or is it a metal tune-o-matic style bridge?

Is the existing base floating or has it been "pinned" to the top? Is there a footprint in the lacquer on the top from the old base that would show if the new base isn't exactly the same dimension?

If the bridge base is already chewed up, what's the condition of the saddle itself? Are there multiple notches for each string? Any notches worn? How's the string spacing?

I guess what I'm getting at is that there are a lot of factors that you'll have to consider before you decide to replace the whole bridge.

Buy a new bridge and fit it to the top.

What kind of guitar? If it's a old cheapo, finding a replacement bridge can be tricky...these guitars need a lower bridge as they were not made with the same neck angle as Gibsons and other more expensive guitars.

You can buy or make a replacement fairly easily...

It depends.
Epoxy is not rubbery if mixed properly. Use 24 hour twin pack and mix for twice as long as you think necessary. Heat the wooden base up in a low low oven to 50°C (hand-hot), this will make the epoxy flow like thin honey. Insert the threaded posts and clean up mess. Support the posts vertical (you need to rig this beforehand) and pop back into oven for 30 minutes. Switch off oven and allow to cool for 2 hours. The epoxy will have set hard but do leave for another 24 hours to strengthen.

A hollow archtop bridge base should not be pinned to the belly because this stops the sound board moving as it is supposed to.

New bases can be had flat or curved. Both need to be fitted to the sound board by putting sand paper across the belly and rubbing the base against the grit. If the sandpaper shifts it will scratch the body, Murphy's Law. A tiny plane (violin maker's) or scraping (knife, chisel, Skarsten, etc) may be needed too. It should actually tilt back slightly towards the tail when done.

These are $20 at Stew Mac. See jefrs's post about using sandpaper to contour the bridge feet to the top plate - very important.

http://www.stewmac.com/product_images/1lg/0193/Archtop_Guitar_Bridge_sm.jpg

Those stew mac bridges will be way too high if it's an old cheapo like a harmony kay or silvertone.

And agreed about pinning bridges. Actually, i am a bit more adamant about that. Anyone who pins an archtop bridge should have their guts spun into guitar strings. What a way to ruin a guitar.

Thanks for your replies. The guitar is a new Hagstrom jazz guitar built in China. The bridge base on these are very much like the ones found on the Chinese made Epiphone ES175 and the Korean made Gretsch 5120. These Chinese bridges are harder to find than you would think. The bridge base on these are not very thick, maybe about 1/4 inch from bottom to top. Bridges from Allparts, Stewart McDonalds and others are much thicker, too tall for the instrument. Even with the thumbwheels all the way down, the bridge can't be lowered to the proper height. I am still searching for a source for Chinese made archtop bridges without success. This is why I am thinking maybe I can repair this one.

Having fooled with a number of arch top bridges I'd use superglue. First mark the position of the bridge with low tack tape to get you in the ball park when you set the intonation when you put the bridge back. With the bridge on your bench make a rig to align the posts. Then pour thin superglue around the posts ans spritz them with accellerator. This will turn the superglue into a super hard plastic. Actually harder than the wood itself which should eliminate any fears of dampening string vibration. It may help to do one post at a time.
Cheers,
Woody

If you are set on repairing what you have the best option may be to drill out the holes and fill them with hardwood dowels then re-drill the post holes.

Cover the top of the base with a strip of masking tape and mark reference points along the edge, so that you can easily and properly locate the new holes when the time comes. Then drill out the offending holes all the way through. Seat the dowels so that the are flush on the top, and slightly protruding on the bottom. When dry sand the bottom flush, then drill the new post holes (you really want to use a drill press for this step.) Prior to re-installing the posts I'd run a few drops of thin superglue into the holes to firm up the wood.

Your other option is to buy a replacement and sand down the base. Looking at a picture of a Hagstrom HJ-500 on MF the bridge doesn't look that much shorter than the Stew Mac version. Remember, if you are replacing the entire assemply then the only things that matter are total height and string spacing. Measure those on your guitar and see if the SM product might work.

Keyser, I've already been down that road. I bought an Allparts bridge here locally. Not only could I not lget the bridge low enough for good action

I'm not sure about the bridge itself, but this base seems pretty much as you describe LINK (http://www.guitarfetish.com/Deluxe-Rosewood-Base-ABR-1-Style-Tuneomatic_p_209.html)

Sorry. Not only could I not get the action low enough, the thickness of the bridge base gave the guitar an odd sounding chunky tone. I contacted Stew Mac by phone and described what I needed. The bridges they carry are on par with the Allparts bridge. I find it odd that with all these guitars being made in China, that no one is stocking spare and replacement parts. Take the Korean made and quite popular Gretsch 5120. If you go to the Gretsch Guitar website, they have a large number of genuine Gretsch Guitar bridges available, but only for the American made instruments. If your Gretsch is Korean, you are out of luck. If they are going to sell us guitars made in Asia, they should back them up with readily available replacement parts. Just sayin'.

Any chance that chunky tone was due to better coupling due to a lack of wobble/give in the bridge? You might be able to alter this by thinning the bridge bottom front to back (reducing the amount of base in contact with the body.) But archtop tone is waay more art than science.


If it were me I'd start with good stability and basic functionality and then try easier ways to alter the tone (string gauge, flat vs. roundwound, etc.)

http://www.grguitars.com/parts_5acoustic.htm

These guys seem to have a few different ones, about halfway down the page

Make a tapered plug and plug the hole,trim the plug,and redrillfor the studs. Or make a new bridgebase.

Thanks for your advice, everyone. I found a Chinese bridge from a Washburn archtop (Washburn guitars are made in China nowadays) on EBay. Judging from the photo, it will be a perfect fit. I didn't need the whole bridge, but you do what you gotta do.

Glad you got it sorted :)

Congrats ;-)

Thanks for your replies. The guitar is a new Hagstrom jazz guitar built in China. The bridge base on these are very much like the ones found on the Chinese made Epiphone ES175 and the Korean made Gretsch 5120. These Chinese bridges are harder to find than you would think. The bridge base on these are not very thick, maybe about 1/4 inch from bottom to top. Bridges from Allparts, Stewart McDonalds and others are much thicker, too tall for the instrument. Even with the thumbwheels all the way down, the bridge can't be lowered to the proper height. I am still searching for a source for Chinese made archtop bridges without success. This is why I am thinking maybe I can repair this one.

Then it will be like the one on my Epi Joe Pass, and yes the replacement bases are too high. But not too difficult to cut down.

It is also a solid bar all the way across, that is important because of the way it sits on the two longitudinal arches, and the thicker than normal laminated top, because it is an electric guitar, not an acoustic with a pickup, thin spruce tops do howl nicely.

And it is shorter than many others because the JP is only 17-in across, smaller than most jazzboxes, a wider one cramps the soundboard.

The f-holes on an archtop are there to let the soundboard flex, not let the sound out as such. Anything that changes that, changes the sound.