So we are really not in the survey business, but we are in the precision manufacturing/engineering business. I have found some great help here without all the negativity while horsing around with an old total station.
I have had a few ideas floating around and proposed to me in the survey world and would like to inquire on opinions.
1. Machined pin caps, either Aluminum or Stainless. I see there are some guys making up Aluminum caps, in which we could probably make one a little nicer for a bit less cost. Or go for Stainless for the best possible life. I am not sure if most here engrave theirs or not? I would prefer to laser etch. Is the mentality to provide a nice finish touch or just put the cheapest cap on? Not sure how much it really matters? Maybe not enough to justify a machined cap and that is just a little off?
2. I was approached to consider refinements to a mobile topo 360* prism mounting system for a mobile unit that has better stability and true bearing to the ground on inclines and on rougher terrain. I am curious if this is really of much need with so much GPS driving forward today? I mean, we could take the NASA approach and come up with a rather trick system to solve any issue in this but I tend to wonder how accurate you really need to be with topo work? Granted when you mount a prism on an ATV and go hit a 30* hill, you are going to get some "not so accurate" data on that hill.
It seems no one else is awake t the moment, how strange. I guess I'll chime in, but my experiences may differ from many others. The first thought that comes to my mind, is that the plastic and aluminum monuments are soft, and will give to the steel (or mystery metal) in the rod when pounding the two together. How would that work with stainless? How will it be tight enough, but not so tight it drives the rod deeper? One of the first things that gets misplaced is the rebar driving tool, and most of our ground is soft, so we only need it occasionally anyways, when we really are mangling the end of the rod. The idea of laser engraved monumentation is appealing, for some corners. I was using stainless steel "dog tags" riveted to concrete form bars when I needed to really mark and describe a corner, but the army surplus store burned down, so now I am not sure what I am going to do. But having 28 characters for 5 lines allowed a good descriptor. That was on high end or complicated jobs, where a corner needed a good ID mark to clear confusion of what it stood for in an area of multiple survey firms doing el rapido cheapo work as they passed by. However, if they are too fancy, a landowner who finds them, or geocacher, etc, may pluck them up and take them home. On most of my jobs, cheap plastic caps fill the need because of the cheap part. I am not the person to really give thoughts on the ATV thing, cause I do my breaks shot by foot, fill in by atv, but we haven't had much call for that kinda stuff lately. Not sure where it is going, now I wonder....
Laser etching of stainless steel would probably be fine for most of us but there are quite a few that want/need to have point numbers on the caps on a case by case basis. Aluminum/brass are soft enough for this to be done but I'm not so sure about stainless. Would you need a plastic insert to provide cathodic protection between steel (pipe or rebar) and the cap?
Andy
most of my caps need extensive stenciling, lot numbers, lot/ section diagrams, section, 1/4, 1/16th#'s, T and R #'s, date, all the things that can't be applied from the factory.
I will order them with my PLS# and that's about it.
There are a few that we order pre-stenciled for a particular project; DOT ROW monuments are some we do that for.
bob james, post: 394124, member: 12050 wrote: So we are really not in the survey business, but we are in the precision manufacturing/engineering business. I have found some great help here without all the negativity while horsing around with an old total station.
I have had a few ideas floating around and proposed to me in the survey world and would like to inquire on opinions.
1. Machined pin caps, either Aluminum or Stainless. I see there are some guys making up Aluminum caps, in which we could probably make one a little nicer for a bit less cost. Or go for Stainless for the best possible life. I am not sure if most here engrave theirs or not? I would prefer to laser etch. Is the mentality to provide a nice finish touch or just put the cheapest cap on? Not sure how much it really matters? Maybe not enough to justify a machined cap and that is just a little off?
2. I was approached to consider refinements to a mobile topo 360* prism mounting system for a mobile unit that has better stability and true bearing to the ground on inclines and on rougher terrain. I am curious if this is really of much need with so much GPS driving forward today? I mean, we could take the NASA approach and come up with a rather trick system to solve any issue in this but I tend to wonder how accurate you really need to be with topo work? Granted when you mount a prism on an ATV and go hit a 30* hill, you are going to get some "not so accurate" data on that hill.
As to item #2, with the ready availability of inexpensive inclinometers it could easily be done so that the position would be corrected for being tilted out of level. I have thought about that for years.
we've done a lot of testing on the difference between a GPS mounted on a 4 wheeler and shots taken at the point, the HI doesn't make much difference at all, neither does the tilt.
Topo's get some random check shots.
They will normally check less than .1'; you need to understand your error budget for a project and just what breaks are necessary to make the best answer.
I don't topo on a 30degree slope sitting on a 4-wheeler, that kinda thing will be walked.
Brass just can't be beat. I find brass caps in coastal Redwood Forest that have been there 5+ decades and they are still shiny as a new penny.
Meanwhile aluminum caps/monuments I set less than 5 years ago are already pitted and corroded.
Dave Karoly, post: 394193, member: 94 wrote: Brass just can't be beat. I find brass caps in coastal Redwood Forest that have been there 5+ decades and they are still shiny as a new penny.
Meanwhile aluminum caps/monuments I set less than 5 years ago are already pitted and corroded.
If you were to set a redwood as the corner....It might last thousands of years.
Dave Karoly, post: 394193, member: 94 wrote: Brass just can't be beat. I find brass caps in coastal Redwood Forest that have been there 5+ decades and they are still shiny as a new penny.
Meanwhile aluminum caps/monuments I set less than 5 years ago are already pitted and corroded.
We work in areas that have amazingly high metal corrosion rates. I have found the plastic Morasse brand caps to be unbeatable with regards to corrosion resistance, and at 7,000 elevations to have no fading or UV damage after 20 years.
bob james, post: 394124, member: 12050 wrote: I have had a few ideas floating around and proposed to me in the survey world and would like to inquire on opinions.
1. Machined pin caps, either Aluminum or Stainless. I see there are some guys making up Aluminum caps, in which we could probably make one a little nicer for a bit less cost. Or go for Stainless for the best possible life. I am not sure if most here engrave theirs or not? I would prefer to laser etch. Is the mentality to provide a nice finish touch or just put the cheapest cap on? Not sure how much it really matters? Maybe not enough to justify a machined cap and that is just a little off?.
Four more than 25 years, I've used the 2-inch aluminum caps that Surv-Kap sells with plastic inserts for 5/8-inch rebar. I like them because for about two bucks you get a marker that is:
- impervious to the elements in Central and West Texas,
- avaliable pre-stamped and with the ability to take additional field stamping as desired (I stamp point i.d. numbers on mine at a minimum),
- perceived by clients (correctly) as very good quality.
Much smaller than 2 inches doesn't leave much room for additional stamping, so 2-inch diameter is about as small as I want to go.
In my opinion, if a person could figure out how to make a marker that met the above criteria and was lighter and even easier to install, that would be an improvement. It would have to resist low intensity grass fires, too, which would possibly let out some thinner metals.
Brass, aluminum, stainless, or plastic, depends on regional variations in terms of corrosion, and what is considered acceptable.
Of all the options, brass (or bronze) is always the best option, for its corrosion resistance and ability to remain readable for hundreds of years, but it is considerably more difficult to stamp than soft aluminum.
In my opinion, (and again regional variations apply) laser etching really is not as good as the deep marks left by stamping.
If you produce a quality aluminum cap at a competitive price, I think that you will find a good market for them. I've found plastic to be OK if set where the caps won't be regularly exposed to UV rays or high ambient temperatures (even if buried under a tenth or two of dirt, if summer temps regularly get over 100 F and the dirt gets direct sunlight, the caps will break down after only a few years). I've found 20 year old plastic caps in WA forests that looked almost brand new. In most other areas, I doubt that they would hold up nearly as well and have a maximum useful life of 20 to 25 years. With regular direct UV and high summer temp exposure, they often don't last more than 3 years. If in an area that is prone to wildfires, they won't last through the first fire, regardless of normal conditions.
Aluminum is more durable than plastic, but depending upon soil content and the amount of precipitation and/or humidity in the area, are prone to pitting that can make them difficult to read after several years. They can withstand a wildfire better than plastic, but have a pretty low melting point as metal goes and can often be completely deformed by a hot grass fire.
Stainless steel would have pretty limited practical uses (perhaps marine environments or in highly corrosive soils) because of the cost and the difficulty in adding marks to the caps. You might find a very limited specialty market for which you could do occasional special manufacturing runs, but not so much otherwise.
Brass still seems to be the best choice for durability in the widest set of environments, for ease of marking, and still remaining somewhat affordable.
A lot of "brass caps" are actually bronze. For most applications there's not much difference in durability, but in a marine environment bronze wins hands down. Salt will leach the zinc out of brass leaving a structurally weak copper sponge, while tin, the primary alloying metal in bronze, isn't materially affected by salt.
After posting the above from memory, I decided to check if my memory was reliable by visiting Wikipedia. While essentially correct, I learned that there's something called "corrosion resistant brass" (which requires very careful manufacture) as well as something called "bronze disease," in which copper chlorides form and eventually destroy the item.
It seems that in metallurgy as in surveying, the answer is "it depends."