# Routing a recess for a patch



## jimshine (Jan 27, 2013)

*Hello everyone, This is a great site. I have been reading it for days. 

I am working on a project and I am trying to figure out the best way to execute it. Basically, I am dealing with a piece of maple that has been damaged. The area is about 4"x6". 3 sides meet seams in the manufacture, one is an outer edge with a 1/8" round over. 

My plan has been to repair the damage, then cut the entire 4"x6" area to the seams and inlay a 1/8" thick piece of maple. The 3 sides will meet seams, the fourth will be on the end, partially concealed by the roundover. 

I have purchased the 1/8" maple, which is planed flat on all 4 sides. Now I need to know the best way to create the recess. Will a straight bit leave me a square enough edge to but the patch in? Or should I go with a mortise bit? 

I appreciate your time! *


----------



## jw2170 (Jan 24, 2008)

Welcome to the forum, Jim.

I feel that you may need an inlay kit to get a perfect fit.

MLCS router inlay set

There may also be other ways to achieve what you are after.


----------



## Mark55 (Sep 6, 2012)

I have an idea of what you are doing and I think there are a couple ways to accomplish this but without seeing the piece it is hard to make a complete suggestion without guessing. Is there anyway to show a picture of it?


----------



## JCJCJC (May 15, 2012)

I rout various shaped recesses regularly when making guitars (pic), once you get used to it it's easy, reliable and very satisfying. Essentially you make a rectangular template and rout inside it, either with a bushing on your router, or with a top-bearing cutter. There's a bit of calculation needed to arrive at the 'offset' - ie the template needs to be a little bigger than the recess you want to create. It will depend on your bushing and cutter combination - try several practise cuts on scrap before attacking your project. The corners of the recess will have radii corresponding to the cutter radius, you'll have to decide to either round the corners of your patch or square the corners of the recess. You have an advantage inasmuch as you can trim your patch to the recess, rather than trying to create an accurate recess to fit a manufactured item.

Practise it, it's not all that difficult. Norm Abrams has shown the technique on his shows, he calls the patch a 'dutchman'.


----------



## Mike (Nov 22, 2004)

Jim, this type of repair will be very tough. The reason is trying to hide the cross grain butt joint. It will be highly visible like in the photo John posted. It would be easiest and cheapest to replace the entire length of the damaged section. The repair can be done and invisible if you are willing to shell out the money for the required supplies. It really depends on the project.


----------



## jimshine (Jan 27, 2013)

Mike said:


> Jim, this type of repair will be very tough. The reason is trying to hide the cross grain butt joint. It will be highly visible like in the photo John posted. It would be easiest and cheapest to replace the entire length of the damaged section. The repair can be done and invisible if you are willing to shell out the money for the required supplies. It really depends on the project.


I am in luck here because I will be refinishing the piece after and it has a shaded edge going to an opaque color on the actual side. So the paint will completely hide the end grain. 



> I rout various shaped recesses regularly when making guitars (pic), once you get used to it it's easy, reliable and very satisfying. Essentially you make a rectangular template and rout inside it, either with a bushing on your router, or with a top-bearing cutter. There's a bit of calculation needed to arrive at the 'offset' - ie the template needs to be a little bigger than the recess you want to create. It will depend on your bushing and cutter combination - try several practise cuts on scrap before attacking your project. The corners of the recess will have radii corresponding to the cutter radius, you'll have to decide to either round the corners of your patch or square the corners of the recess. You have an advantage inasmuch as you can trim your patch to the recess, rather than trying to create an accurate recess to fit a manufactured item.


This is pretty much what I had in mind. I am experienced at routing guitars with the usual bearing guides and acrylic templates.The idea was to create the patch with square corners (I have a corner chisel). Lay the patch in place and but 3 large pieces of acrylic template stock against the 3 sides of the patch and double stick tape them down and use that as my guide. But the offset makes sense. I have to figure that out. The radius at the top of the edges is what I want to reduce as well. What bit will create the sharpest edge? 

The end result just has to have the tightest seams possibles viewable from the top.


----------



## bobj3 (Jan 17, 2006)

http://www.routerforums.com/email-router-tips-members-only/2390-repairing-router-chipout.html

===


----------



## JCJCJC (May 15, 2012)

Hey Jim - first of all, my pic was a guitar in course of construction, just to make the point - it is nowhere near the finished standard which will be a hell of a lot better, I spend months on each guitar getting details right.
The offfset issue arises if you use a bushing, it's logical and easy to calculate it. Once you know what size rectangular hole you need, you make the template. I find the easiest way to make an accurate rectangular-hole template is to run a strip through the table saw, set to the short side of the rectangle. Chop that strip with an accurate chop-saw, space the two cut ends apart the length of the long side, and glue additional strips on either side. I use scraps of laminate flooring for those, and I get to within 0.5mm of the size I want usually, at the initial stage. I use masking tape to fine-tune the template down to the final dimension.
The radius at the corners is governed by your cutter - you do a trade-off between fast removal of material and small radius. A planing or bottom-cleaning bit will cut quickly and leave a clean flat surface on the floor of your routed area.


----------



## jimshine (Jan 27, 2013)

Sorry if I came off as judging your guitar. That wasn't at all what I had in mind. I was just clarifying what my goal is. The timing makes it seem like that. 



JCJCJC said:


> A planing or bottom-cleaning bit will cut quickly and leave a clean flat surface on the floor of your routed area.


Now that is a bit I have to investigate! Thanks!


----------



## JCJCJC (May 15, 2012)

I get bits from George Hsu <[email protected]> on Ebay, if you email him he'll list whatever you want on a buy-it-now basis, I have always found him 100% to deal with. I use those bottom-cleaning bits for the pickup routs, neck pockets and control cavities on my guitars, so you'll get more than one project from them.


----------



## jimshine (Jan 27, 2013)

I am going to test it on a piece of pine. Make a patch, then make a template of it in something thick and make the recess with my template bit. Chisel the corners, and glue in the patch. Of it is gappy, I will have to figure something else out.


----------



## JCJCJC (May 15, 2012)

jimshine said:


> I am going to test it on a piece of pine. Make a patch, then make a template of it in something thick and make the recess with my template bit. Chisel the corners, and glue in the patch. Of it is gappy, I will have to figure something else out.


I'd make the recess first. Much easier to cut a patch to fit a recess than the other way around.


----------



## MAFoElffen (Jun 8, 2012)

Was waiting for that picture also, but no matter.

Just a few tips on repairs that I use in restoration carpentry that might help...

3 sides are at a joint. One side is the continuation of the old maple... correct?

So how you usually do something like that side or continuing on a piece and the joint not turn out as being too visual... Cut out the recess on the three sides along the joint using a template or guide... When you go to cut the fourth side, do not cut it straight down, but rather at an angle such as 15-30 degrees. Blend in the bottom of the recess flat. Finish with a wood chisel.

Match the grain and wood base color. Orient the grain to match. Cut the patch to a bit of excess. Cut an "almost" matching beveled edge, just a 1/4 degree shy of being the same. That way if any of the lower part of that bevel is proud, it won't be visual at the top side of the patch. Trim the other 3 sides, trimming the side opposite the bevel last. Cut that side so the bevel just barely drops down into it.

Visually, as you look at it, it's easier to hide a joint and blend it in if you're not able to look straight down into it. In the sanding, if you sand just to direction of the beveled edge (assuming the grain goes that way), it will feather it and blend itself in. Rub a bit of fine saw dust from trimming that joint into the joint after you wipe the excess away.That should help tighten the edges together.

It you do it this way, seal coat it first, before you stain. If not, the feather edge may turn out darker where the wood is thin. This will be more apparent if you chose a sharper angle for your joint. 15 degrees is usually a good choice if you get tight joints. Sharper if you don't trust yourself joining as it's easier to blend in, but harder in the finishing (stain) phase.

Reference on this would be a scarf joint.

Another would be to dig out any rot or damage. Fill where you needed to remove. Sand down a "very" shallow recess. Apply a veneer patch... Wood patch the blend edges. (include stain into the wood patch before applying). Finish sand to feather the edges of the patch. Stain to match.


----------

