Finishing questions
I've finally made a hornbow that warrants being finished properly and decorated.
I live in England where the r.h. rarely falls below 50% and has been 80% or above for about 5 months now therefore waterproofing is important for me. I want to use this bow in a 2 day 3d competion in a couple of months and last time I went it rained heavily, if the same thing happens again I don't want to have to be worring about the bow/humidity.
So my questions are is there any difference in water resistance between the birch bark method of covering or using leather?
We have plenty of birch around here but none that i've found is suitable for a bow covering. I have sometimes found pieces that look ok but when i've seperated them into single sheets there are too many little holes, the natural holes not ones i've made! Maybe it's just how it grows here?
Does anyone know of an online supplier or suitable birch bark? I have seen on Dictums site that they sell it but I haqve no idea if it would be suitable?
http://www.mehr-als-werkzeug.de/product ... -20-cm.htm
Also can anybody recommend a good supplier for thin enough calf leather? As I have drawn a blank in my searches so far.
Many thanks.
I live in England where the r.h. rarely falls below 50% and has been 80% or above for about 5 months now therefore waterproofing is important for me. I want to use this bow in a 2 day 3d competion in a couple of months and last time I went it rained heavily, if the same thing happens again I don't want to have to be worring about the bow/humidity.
So my questions are is there any difference in water resistance between the birch bark method of covering or using leather?
We have plenty of birch around here but none that i've found is suitable for a bow covering. I have sometimes found pieces that look ok but when i've seperated them into single sheets there are too many little holes, the natural holes not ones i've made! Maybe it's just how it grows here?
Does anyone know of an online supplier or suitable birch bark? I have seen on Dictums site that they sell it but I haqve no idea if it would be suitable?
http://www.mehr-als-werkzeug.de/product ... -20-cm.htm
Also can anybody recommend a good supplier for thin enough calf leather? As I have drawn a blank in my searches so far.
Many thanks.
Congrats with the bow :D
Some time ago I bought some bichbark from Dictum. Have not used it yet , but I hesitate to recommend them for our use because of quite a lot of irregularities that may become small holes. Nice flat sheets though.
I think the bark I harvested myself was better, because I could cut strips between the irregularities. I think you must find several clean strips and put them together, overlapping a little.
Outside the bark I used a varnish consisting of 70% raw cold pressed linseed oil, and 30% chinese Tung-oil. It seems to work very well, it do not crack, and seems to protect quite well against moisture. Haven't drowned the bow tho. In addition it's nice to work with, and smells very little, as it don' contain any solvents. (The varnish I got hold of is called "Le Tonkinois" but there may be others. Its intended for wooden boats)
Sorry, don't know any suppliers for leather....
Some time ago I bought some bichbark from Dictum. Have not used it yet , but I hesitate to recommend them for our use because of quite a lot of irregularities that may become small holes. Nice flat sheets though.
I think the bark I harvested myself was better, because I could cut strips between the irregularities. I think you must find several clean strips and put them together, overlapping a little.
Outside the bark I used a varnish consisting of 70% raw cold pressed linseed oil, and 30% chinese Tung-oil. It seems to work very well, it do not crack, and seems to protect quite well against moisture. Haven't drowned the bow tho. In addition it's nice to work with, and smells very little, as it don' contain any solvents. (The varnish I got hold of is called "Le Tonkinois" but there may be others. Its intended for wooden boats)
Sorry, don't know any suppliers for leather....
I have wondered about the quality of the bark from dictum too. A year ago I bought some from this source:
http://birkenleder.de/produkt/birkenrinde-50x60cm/
I wanted to do the covering for an older bow that I have, as a test. They get the bark from Russia, it seems that they use older trees, there's always a bit moss on such a plate, and always some spots that are gnarled and warped. It's hard to make longer strips that would cover the better part of the limb. You'd have to make many small strips. Like Lurz said, overlapping.
Recently I saw that somebody cut down a young birch close to where I live. It was just perfect material. Smooth and not gnarled, no warping. If I were you, I'd get that stuff.
http://birkenleder.de/produkt/birkenrinde-50x60cm/
I wanted to do the covering for an older bow that I have, as a test. They get the bark from Russia, it seems that they use older trees, there's always a bit moss on such a plate, and always some spots that are gnarled and warped. It's hard to make longer strips that would cover the better part of the limb. You'd have to make many small strips. Like Lurz said, overlapping.
Recently I saw that somebody cut down a young birch close to where I live. It was just perfect material. Smooth and not gnarled, no warping. If I were you, I'd get that stuff.
I would make a full bark covering like on old bows.
This looking good. http://countrycraftsupplies.com/birch-bark/
Russians selling nice bark as I know. Just have to find the place :)
Have a friend in germany who ordered from there. It was looking like the same stuff like in the link.
Find this videos few minutes ago.
http://www.youtube.com/playlist?list=FL ... vt8xzYzsDA
I was harvest some for myself. If find a tree and have a knife, schould do the same. The best is springtime so do it soon. ;)
This looking good. http://countrycraftsupplies.com/birch-bark/
Russians selling nice bark as I know. Just have to find the place :)
Have a friend in germany who ordered from there. It was looking like the same stuff like in the link.
Find this videos few minutes ago.
http://www.youtube.com/playlist?list=FL ... vt8xzYzsDA
I was harvest some for myself. If find a tree and have a knife, schould do the same. The best is springtime so do it soon. ;)
Birch bark is very waterproof. I'm lucky to have access to large clean sheets of it and I would put it ahead of any other natural covering.
You could also try looking at bookbinding suppliers as a source of thin leather though. It really shouldn't be that hard to find.
Here's one; http://www.russels.com/specialistleathers.shtml
You could also try looking at bookbinding suppliers as a source of thin leather though. It really shouldn't be that hard to find.
Here's one; http://www.russels.com/specialistleathers.shtml
2 months is not much, so I suggest to use modern paints. Acrylics driy fast and can be top-coated with an oil base varnish. For fast drying a thin coat of modern spar/some tung/linseed is good.
Leather is easier to apply and provides good protection when coated with paint and oil based varnish. The question is, do you really want to seal the bow so much? The coating doesn not allow the moisture to escape just as much as it does not allow the moisture to get in.
If the humidity in the shop is above 40%RH, I would put the bow in the dry box at 35-40%RH right now for at least a week to dry. Then cover with leather using contact cement in place of the wet glue and keep it in the box all the time (take it out only to paint). You will have a nicely dried bow for the tournament (make sure you have a plastic bag for the bow there and avoid exposure to sun as much as possible).
Silica gel crystals are good as the drying agent in the box, but the RH has to be monitored inside to avoid over-drying. Dehydrated calcium chloride will keep the RH at 30-35% without the need to check the RH.
Adam
Leather is easier to apply and provides good protection when coated with paint and oil based varnish. The question is, do you really want to seal the bow so much? The coating doesn not allow the moisture to escape just as much as it does not allow the moisture to get in.
If the humidity in the shop is above 40%RH, I would put the bow in the dry box at 35-40%RH right now for at least a week to dry. Then cover with leather using contact cement in place of the wet glue and keep it in the box all the time (take it out only to paint). You will have a nicely dried bow for the tournament (make sure you have a plastic bag for the bow there and avoid exposure to sun as much as possible).
Silica gel crystals are good as the drying agent in the box, but the RH has to be monitored inside to avoid over-drying. Dehydrated calcium chloride will keep the RH at 30-35% without the need to check the RH.
Adam
Thanks for the ideas.
I've decided to go down the leather route. I may have found a supplier of horse rump leather that is thin enough. Failing that I have some calf leather coming anyway.
I decided that buying the birch bark would be a bit hit and miss. I may get something useable but...I will keep looking for suitable birches around here.
Making a 'dry box' is a very good idea, it hadn't even occured to me. I have ordered some silica gel and also some dehydrated calcium so that I can get it nicely dried. Unfortunately 40% RH only happens here for a couple of weeks a year! As for if I want the bow sealed very well - I think if I keep the bow in the dry box all the time that I don't use it then it will reach equilibrium there and will be 'safe' for me to use it in the pretty much always high humidity we have the pleasure of here. I think I would rather err on the side of caution and have it on the dry side and not have to be worrying about rain or high humidity.
What ratios of linseed to tung oil do you recommend? I have some Rustins yatch/spar varnish but it is very thick, I normal dilute it 50/50 with white spirit. If you think the spar/linseed/tung oil mix is the best for me to use would you use the spar varnish undiluted with white spirit?
Many thanks everyone.
I've decided to go down the leather route. I may have found a supplier of horse rump leather that is thin enough. Failing that I have some calf leather coming anyway.
I decided that buying the birch bark would be a bit hit and miss. I may get something useable but...I will keep looking for suitable birches around here.
Making a 'dry box' is a very good idea, it hadn't even occured to me. I have ordered some silica gel and also some dehydrated calcium so that I can get it nicely dried. Unfortunately 40% RH only happens here for a couple of weeks a year! As for if I want the bow sealed very well - I think if I keep the bow in the dry box all the time that I don't use it then it will reach equilibrium there and will be 'safe' for me to use it in the pretty much always high humidity we have the pleasure of here. I think I would rather err on the side of caution and have it on the dry side and not have to be worrying about rain or high humidity.
What ratios of linseed to tung oil do you recommend? I have some Rustins yatch/spar varnish but it is very thick, I normal dilute it 50/50 with white spirit. If you think the spar/linseed/tung oil mix is the best for me to use would you use the spar varnish undiluted with white spirit?
Many thanks everyone.
Just a quick update on how my 'waterproofing' went for the National Champs.
In the end I used birch bark and leather strips on the edges. Then 4 coats of Rustins Plastic Coat varnish.
I also made a plywood box with a seal around the lid and had a few bags of calcium chloride dihydrate inside. The r.h. inside the box stayed constant at 40 - 45%. Thanks for the idea Adam.
The bow held up just fine in heavy rain and high humidity the whole weekend. The first day was plagued with heavy rain, the second day started off raining but eventually dried up however the humidity was over 70% the whole time. I was expecting to see some string follow after being strung and shooting all day but there was no more than usual.
If i'd have had ten of these bows I could have sold the lot! One after another people came over to me asking ' is that a real hornbow?' :)
In the end I used birch bark and leather strips on the edges. Then 4 coats of Rustins Plastic Coat varnish.
I also made a plywood box with a seal around the lid and had a few bags of calcium chloride dihydrate inside. The r.h. inside the box stayed constant at 40 - 45%. Thanks for the idea Adam.
The bow held up just fine in heavy rain and high humidity the whole weekend. The first day was plagued with heavy rain, the second day started off raining but eventually dried up however the humidity was over 70% the whole time. I was expecting to see some string follow after being strung and shooting all day but there was no more than usual.
If i'd have had ten of these bows I could have sold the lot! One after another people came over to me asking ' is that a real hornbow?' :)
What was the bow style that you competed in?
And do you have a picture of the bow? What design is it?
And do you have a picture of the bow? What design is it?
Yea Mike, don't be a meanie. Show us a picture.
It was in the 'primitive' class of NFAS field.mongolianarcher wrote:
What was the bow style that you competed in?
And do you have a picture of the bow? What design is it?
I probably should take a photo or two to show - i'll try and get some nice ones.
The design is sort of like a holmguaard bow but with a horn belly.
I have some deer skins that I am going to soak and scrap for rawhide, they are close to calfskin thickness but I believe stronger. I also have some brain tanned but saving that.
Anyhow I am going to try covering at least one bow with the deerskin, starting first on a self bow of ash and one of hickory. Both bows I liberally coat with tung oil, I will let that soak in more then put the rawhide on. I will be trying it on one of the composites in process after the backings are on both sides and its tillered.
I do like the birch bark, and want to use that also. Our RH here in Michigan is very much like that in Ontario right across the border.
Anyhow I am going to try covering at least one bow with the deerskin, starting first on a self bow of ash and one of hickory. Both bows I liberally coat with tung oil, I will let that soak in more then put the rawhide on. I will be trying it on one of the composites in process after the backings are on both sides and its tillered.
I do like the birch bark, and want to use that also. Our RH here in Michigan is very much like that in Ontario right across the border.
What glue are you going to use to glue the rawhide onto a tung oil finished surface?
The wood surface has to be thoroughly cleaned, a number of solutions for that, I have been putting sinew on cleaned surfaces for a very long time. Hold off oiling any surfaces you know are going to be glued/sinewed. Acetone is one I have used with effective results. And most often use. Once the surface is cleaned use the glue of your choice.
Mikekeswick go for a birch bark ! It has very much tar in it and serves very well for your purpose.
The holes formed in an attempt to separate layers of birch bark occurs when bark is harvested at the wrong time. In the spring the bark is strictly different than the fall. I fear recommend to you our method because I do not know characteristics of the UK flora that well , but in Eastern and Northen europe bark is collected immediately after the summer solstice when the bark and leaves are strongest - it is the end of June, first week of July. It is working for centuries at last in here.
If you do it with the skin it would be very advisable to know which way the skin is tanned. Recommended to be used with vegetable tanned leather and softened with natural fats but as you can guess all that have a impact on quality of glueing properties particularly if in tanning process is used chrome or potassium alum. But if you use raw hide it soak up all water so bark or fish skin or snake skin would be the best!
The holes formed in an attempt to separate layers of birch bark occurs when bark is harvested at the wrong time. In the spring the bark is strictly different than the fall. I fear recommend to you our method because I do not know characteristics of the UK flora that well , but in Eastern and Northen europe bark is collected immediately after the summer solstice when the bark and leaves are strongest - it is the end of June, first week of July. It is working for centuries at last in here.
If you do it with the skin it would be very advisable to know which way the skin is tanned. Recommended to be used with vegetable tanned leather and softened with natural fats but as you can guess all that have a impact on quality of glueing properties particularly if in tanning process is used chrome or potassium alum. But if you use raw hide it soak up all water so bark or fish skin or snake skin would be the best!