Heat gun or warm sunlight will help. Don’t be shy about sanding lightly between coats. The first coat should be very thin for just that reason — bubble avoidance. It will also raise the grain so a bit of light sanding is order. It comes down to technique and experience. By the way, that sign looks great!
A painted surface can also be made more smooth with some fine sanding. Sounds contrary, yes.
Shellac dries very fast. You can try the heat but since it dries so fast that may not work. I seal almost all my project with the product @CrookedWoodTex suggested the Zinnser Universal Sanding Sealer. I wipe it on let it dry about 30 minutes and sand lightly with 220/320 grip paper by hand and apply a second coat if needed. The spray version has a lot more carrier to make it spray so maybe try the wipe on version instead of the spray. The bubbles are air escaping from the wood. The purpose of the shellac is to seal the wood. You can seal with shellac and then apply another top coat either water or oil based or simply 2-3 coats of shellac. Shellac is a good finish and traditional finish but it is not a good topcoat for items that get worn or used by hand. For a wall hanger that will seldom be touched it is a great finish and easy to touch up or refinish.
Thanks! This is what I did today with a couple very lite coats and followed by low heat and the bubbles came and gone with it.
I appreciate everyone’s insight. This was my first time using this spray on shellac and really like how it worked on a couple other signs I completed. This wood was more dry that the plywood I guess.
[Etch8SonsCustoms]
How did you get the equipment, loader and truck, to show up so well? Can you tell me what bit you used and the depth of the design?
I’m guessing you painted the board black and then sanded it off?
Thanks
I did a couple steps to get that.
Can you be more detailed?? Just kidding. Excellent process and I will try that for sure.
THANKS
Looks good. I
Am hoping though that 8 in your profile name is a stand in for the & and not an indication of the total number of sons. I have 2 and a daughter. That’s enough to drive me crazy and limit my shop time.
Your plaques are very nice. The picture with the semi-round eyelet always has me concerned. I have used those myself and everything always gets crooked. Finding the perfect center and that the wood is perfectly balanced is tricky. Personally I use a key hole bit and make two. Then I engrave the spacing and supply a couple of hollow wall hangers with screws.
Here is an example.
In the image you can see I carved 8" center to center to aid the recipient with hanging the plaque. It may just my pet peeve but I hate to see a picture hanging crooked. The plus is you dont need the hanger but you do need the hollow wall hangers. Relying on the recipient to have some may never get your plaque hung on the wall.
Nice work.
I appreciate all the advice! I agree about these hooks. I’m hoping it’s even.
I have been wanting to do keyholes, but I haven’t been able to try it out yet. I do have the router bit, but my plunge router is a little hard to get to right now. Do you use the keyhole bit on your CNC? I was thinking that bit wasnt fit for CNC use.
I use my Keyhole in my CNC all the time. It works great. Takes longer to set up the cut then the actual cut. There are several great tutorials on the web and Carbide Create even has the tool path.
Scott
The keyhole toolpath has been in CC for some time. I use a Frued 70-104. Go to the OEM website to get the exact specs of your keyhole bit. Be careful about F&S from the OEM. For instance the Freud website has fantastically high F&S. I think they are calculating for an industrial CNC and not a hobby CNC. Simply substitute your bit measurements for what I have and also your unique tool number.
The basic operation is to draw a circle the diameter of your keyhole bit. Then tell the toolpath how for to plunge forward. Super easy. The keyhole toolpath plunges full depth for the screw head and then moves forward the amount you set in the toolpath. Then the bit reverses and plunges back out the entry hole. Just make sure you plunge far enough to have some meat in the wood where the screw will actually hang on the wall. If you make it too thin the keyhole could break out.
The keyhole bit diameters are as follows. The diameter of the keyhole bit at the bottom. Then the thickness of the large bottom of the keyhole bit. Then the shaft of the smaller part of the keyhole bit. So you can calculate about 1/8" of meat in the smaller slot and likely about 1" of distance the keyhole will move forward.
Here is my custom tool database for the keyhole bit.
| number | vendor | model | URL | name | type | diameter | cornerradius | flutelength | shaftdiameter | angle | numflutes | stickout | coating | metric | notes | machine | material | plungerate | feedrate | rpm | depth | cutpower | finishallowance | 3dstepover | 3dfeedrate | 3drpm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 701 | Freud | 70-104 | 701 Keyhole | end | 0.39 | 0 | 0.25 | 0 | 0 | 2 | 0.125 | 0 | 10 | 60 | 16000 | 0.4375 | 1 | 1 | 60 | 16000 |
Thanks! I will give it a try, my bit came in a $100 assortment from Lowe’s so I’m not not I have the specs on it but I’ll give it a try and if needed but a new bit.
Just measure the bit and enter your measurements in the custom tool database. Even using my tool database would work. You are just drilling a hole, plowing forward. The key is that the entry plunge is big enough around to get a #8 pan head screw through. You could slow down plunge rate and ipm down and bring them up till you are comfortable.
Just get a piece of scrap and practice
Shellac and poly both dry very quickly and the result is that the wood may have some moisture content that cant escape, thus bubbles appear. First, make sure your wood is dry 7-10% level , if not try warming the board somewhat and avoid spraying in cold environments. You can use a hair dryer as noted, but from your pictures, you may be attempting too thick of a coat instead of multiple lighter coats. Tom
Good point, I was not thinking of moisture in the wood. I may have put the first layer on thicker but not by much if anything. I tried the heat gun and it definitely helped. I think next piece I’ll try heating it with the heat gun first then quickly after.
I’ve had bubbles in shellac even when the wood was kiln and vacuum dried.
My theory is that some alcohol wicks into the wood, gets trapped under the now drying shellac, turns into vapour and causes bubbles. Temperature is a contributor to this, higher temperature causes the alcohol in the shellac on the surface to evaporate faster.
Just my 2 cents, YMMV or YKMV(for us metric users).
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